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post #1 of 439 Old 08-13-2013, 12:59 PM - Thread Starter
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I have been working on a diy black-screen for a little while now and have made a little progress. I’m not 100% there yet but I’m not far off either. I can see this is an area that is of interest to people so I thought I’d share my results and maybe get some help and advice on the last few challenges.

Here is a link to one of my earlier tests of my diy black screen material. The bottom half of the screen is painted with screen goo high contrast grey. I though this would be more appropriate than white for the early tests as this is a commercial solution for ambient light with a painted screen (well in theory anyway). As I am making the screen for myself, I don’t benefit from making it look good artificially. That would just hurt me.

http://www.youtube.com/watch?v=6-LDZ1LwAVU

The screen in the test is 80 inches. I am not going to make my 120 inch screen until I am done testing but I expanded the image to make sure my results didn’t just look good because the screen was small. I also calibrated the projector for the grey screen (as far as possible) so as not to give the black screen an unfair advantage. The room is brightly lit from 3 directions. A light above with three 100 watt bulbs. A 100 watt side light and the blinds are open on a sunny afternoon directly opposite the screen which is a touch environment for any screen. I think anyone could agree that it is as bright as anyone would realistically expect to watch a movie in. I could move the screen closer to the window to get more sun light on it but that wouldn’t reflect my brightest reality, it would just make the job even harder or be showing off!

You can see in the video that the “high contrast” paint looks anything but in a room that bright. The black screen looked watchable. It wasn’t perfect but encouraging enough to continue the experiment.

In doing my research, I saw that all the high-end screen manufacturers describe their materials as “multi layered”. Not giving much away but it’s a start. It makes sense. A painted screen needs the surface layer to do multiple jobs which are in conflict of each other. Reflect the whole color spectrum, be dark enough to help with contrast and not cause color shifts, smooth enough give a clear image but also diffuse light so you don’t get hot spots. The mixed painted screen is a compromise and leaves you with a fairly light color that has to be neutral. Too dark and you won’t get any image or an image with color shift. Too reflective and smooth and you get hot spots. Separating the layers so that each one can be the best at its job makes sense in theory as long as the let enough light pass to allow you to take advantage of each layer. So as a minimum, I needed 3 layers. A reflective layer, a tinted layer and a light diffusing layer. Think of diffusing as being the difference between a screen and a mirror in terms of the type of reflection.

The screen in the clip has 3 separate layers. The first is aluminum paint for reflection. When dry, I added a separate layer of black paint. When dry, I added a final layer of translucent screen paint. The final appearance was dark grey. Somewhere between the black diamond 0.8 and the 1.4 gain screen (in color only). In reality, it wasn’t grey but had that appearance from the black being visible through the translucent top coat. Normally a screen that dark would not give a good image, not just because it isn’t neutral. A paint that dark as a single layer would be too dim to reflect anything.

The translucent layer is almost transparent when projected on which allows me to take advantage of the black background. Essentially achieving blacks with pigment instead of darkness. On a white screen, the absence of light can only look like a washed out grey with the lights on. With the lights off, the absence of light is black like all the other dark surfaces. With the lights on, black can only be achieved with pigment. This is true even on really bright professional projectors. I have tested with devices up to 8,000 lumens and all look washed out in a bright room with a white screen.

Now, the screen in the clip was an early test and is far from perfect. If you paint on a piece of plexi-glass and hold it to the light, most paints let some light through. The undercoat can have more of an impact than one might think, even with multiple coats. The water based aluminum paint from auto-air recommended for black widow mix is terrible for this. 6 layers and I could still see light shining through it. The exception to this is black paint which seems to kill most light, even if fairly thin. On that screen, I wasn’t able to take advantage of the reflectivity of the aluminum paint so all of the reflection was from the translucent layer. This wasn’t a terrible problem and it worked fairly well. The blacks looked amazing considering how bright the room was and compared to the best efforts of a commercial high contrast paint. For an ambient light screen though, it would be nice to have the option of adding some gain.

The word tint used by screen companies stuck. They don’t use paint in the high end screens for contrast. I think the reason is that tinted film lets light pass so they can use more layers. Many of the tinted window films are designed to allow light to pass without changing color. Some are also designed to not be reflective and to stop glare. All useful properties in this quest.

The other problem is the translucent paint and specifically, my ability to apply an even smooth coat. It isn’t very forgiving. One mistake and you have to start over. Even with the best of rollers, it is also hard to make it really smooth like a pro screen. Using a solid screen printing roller, I got fairly close in the clip. From watching distance, it is smooth enough but not perfect.

TBC
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post #2 of 439 Old 08-13-2013, 01:37 PM - Thread Starter
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For the next test, I changed a few components a little. Firstly, I added aluminum ink to the aluminum painted layer. For some reason and I won't pretend to understand all the reasons for my results, the ink seems far more reflective. I was never able to get a major uplift in gain from the aluminum paint. I assumed it was user error on my part (and it still might be). When making my black widow screen, I never saw a major difference to using a similar color made with other types of paint. I'm sure there is some but not like I saw with the professional screens. If I paint just aluminum paint and project onto it, is isn't really that bright considering it uses one of the most reflective metals on the planet as it's main ingredient. Now with aluminum ink, on it's own, it was blinding. It was brighter than the pro silver screens used for 3d. Obviously it also hot spots and isn't a solution on it's own but with other paints, it really makes a difference.

Off topic, I added some aluminum ink to my black widow mix and it increased the gain on that too. Maybe because ink gives better saturation or a smoother finish???

It''s greater saturation makes it useful for mixing with black paint. Aluminum paint mixed with black gave me a useless dark grey. Ink with black paint gave me a reflective silvery black.

My conclusion was that I had overdone it a bit. Check out the clip:
http://www.youtube.com/watch?v=SRyurpNqd4U

The screen still outperformed my grey screen and my black widow screen in a room that bright but it was too reflective and I lost some contrast.

I turned the brightness on the projector all the way down and turned on dynamic black (local dimming) and got some improvement but the extra reflectivity made the imperfections in the top coat even more noticeable. Check out this clip.

http://www.youtube.com/watch?v=Y0pi8y2m34k

In the clip above, I had gone out and bought a paint sprayer from home depot for $80 to get a smoother finish. I made the mistake of painting with the screen upright which caused the translucent paint to run. While it is smooth on most of it, there are several patches of obvious mistake. I am sure that with enough tries, I could perfect that eventually but the translucent paint is expensive and every mistake means starting over. For testing, I didn’t think it was worth starting over and wasting more paint although for the finished screen I would.

My 2 take aways were that I needed a tinted film for the middle layer and light diffusing material for the top layer if I want a professionally smooth surface.

Searching for these materials at a reasonable cost is difficult because you are looking for something that was made for a different purpose but that still works. 3M seem to make all kinds of reflective, tinted and light diffusing films that on paper sound perfect but they are so expensive that you may as well just buy a black diamond screen and tell your kids that college is out. It doesn’t help that they come in roles that are tiny or 3 miles long. Every one of their products, while superior, is out of the question for any diy project.

Being a resourceful guy, I found lower cost alternatives for a lot of it. For the top layer, I had some success with a translucent rear projection film. Check out this clip of the test:

http://www.youtube.com/watch?v=PJSIndo70v4

On the back of this fabric is a layer of black paint, powder-sized glass beads and aluminum ink and paint. The finished surface looked close to that black-screen appearance we want. A little darker than the black diamond 1.4 gain material (as they depict on their site). It could be made darker with more black paint or darker film but I’ll get to that.

I was fairly happy with that last test. The front surface was silky smooth and a great light diffuser. I could say hand on heart that there was zero hot spot potential but nothing that off-axis positioning of the projector wouldn’t fix. I believe the real black diamond has hot spot issues too so for authenticity…. The image clarity was great and the brightness was good. Not as good on the contrast side as my first experiment but not far off. The black borders on the movie were very black for a room that bright. At this point, we are in a different league to what could be achieved with a white screen in this level of light so no point in comparing.

I conducted a similar test with transparent screen material and got hot spots and no image. I would still like a darker light diffusing layer though to make it darker. It’s interesting. Black diamond has great marketing with their “it looks like a plasma” ads but in reality, the more popular 1.4 gain screen is far more grey than black. If all I wanted was to replicate this color in my screen then I could stop at this point.

The problem is, I know I can do better and I have more material on their way to test. Specifically, I am being sent samples of some light diffusing material that was specifically made for screens and some window tint film that seems suited for my contrast layer.

TBC
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post #3 of 439 Old 08-13-2013, 02:05 PM - Thread Starter
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The images above show a crude test with a sample of tinted window film instead of paint for the contrast layer. The first shows the film. A 35% tint (a larger number indicates less tint, smaller % is darker). Not the best film possible as it uses metal layers. The ceramic non-reflective film would have been better. I was also thinking it might be too dark but it's not horrible. It would be too dark if it was the top layer though. The second image shows my light diffusing layer for this test. In this case, a piece of transparent rear projection film. 3rd is the reflective layer. This is a piece of aluminum sheet with a polished but still matt finish. For my final screen, I am thinking of using a piece of aluminum sheet as the back layer for reflection and to keep the screen rigid. The black diamond zero edge is backed with aluminum. Online, a 4 foot by 8 foot piece can be purchased for less than $150. Not the cheapest diy option but still lower than any of the high end commercial options. Also, not a bad way of creating a flat rigid surface for people who don't have great diy skills (like me for example).

The 4th pic shows what they look like when held together. Kind of like an off plasma don't you think? Where have we heard that description?

The 5th shows the results of my crude test which actually looked fairly good. If I held it off axis, there were no hotspots. On axis there were so this would only work for people who have their projectors on the ceiling or floor.

I can see the challenge becoming more about getting a smooth professional finish that doesn't hot spot. I hate making choices like that but I may not have to.

I have ordered some material which is very dark grey (nearly black) that I think could function as the light diffusing layer as long as the layer underneath is reflective enough. Here is a pic of another crude test with a similar (although not as dark) material.


This material does not hotspot and also gives us that dark appearance.

The final pic shows a quick summary.
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From left to right. 1 the Sony Dynaclear. I love that fabric. I wish I could buy a roll of it. It's a shame it's too small and badly built. It was the only low cost screen with high end fabric ever made in my opinion. Wasted in Sony's hands. 2 the dark fabric I just mentioned. The reflection is from my flash, not the projector btw. 3rd is my unrelated diy glass bead screen. 4th is the diy black-screen material from the first test.

I am waiting for delivery of samples of custom (and low cost) light diffusing material, 50% ting film, Aluminum sheet and black screen fabric that could potentially be my front layer.

More pics when those materials arrive. In the meantime, if anyone has any ideas for a light diffusing translucent layer that is smooth enough for a good image, I would love to know.
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post #4 of 439 Old 08-13-2013, 02:33 PM - Thread Starter
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One final thing to bring the test up to date is the light rejection component. The closely guarded secret of DNP and Screen Innovations is the micro louver technology their screens use to black light from the sides or above or both. This is similar to the technology used in the privacy screens you see on monitors to stop people seeing the screen from the side. Perhaps some of you noticed that the new Black diamond now claims 4 way light rejection? Coincidently, the latest generations of privacy filters claim 4-way privacy.

If you don't know (I didn't) a louver is the term for those blinds that only let light in front certain directions. Micro louvers are made by printing tiny horizontal lines on transparent film. Using multiple films, they can be positioned to create tiny louvers to block that unwanted light from certain directions. That is also the reason why light from the same direction as the projector can't be blocked. It is also the reason why the screen goes dark when you go off center. It's not just because it's retro reflective.

Check out these pics of an ipad privacy screen in front of a screen.





Now, the easiest way of creating a black-screen at home would be to buy a giant privacy screen. The only problem is that nobody sells them. I have looked, and looked (and looked). The largest one I could find was 45 inches and that was more than $400. Not exactly useful for a bargain diy screen. I was reminded that one of my suppliers sold a micro louvered window film for rear projection but the price for anything above 100 inches was so large that I remembered why I discarded and forgot about it the first time.

So, if anyone knows how we can get a micro louvered film of 100 inches or more at a price that doesn't singe the old nasal hair, it would be instant light rejecting screens for everyone. You wouldn't even need to change your existing screen. If these companies weren't so secretive and afraid that someone might discover the cash cow, they might have even had the sense to make a screen with a removable or retractable filter so you could enjoy a wider viewing cone in a darker room and only use the filter with it's limitations when the room had to be bright. I guess most people sit in front of their screens anyway so it doesn't matter.

3M claim to have a patent on this technology but I don't know what that covers. Perhaps these screens are so expensive because they have to pay a large royalty to use the technology or perhaps they just charge a lot because it's a secret.

Now, if these filters were used as the second layer instead of the first, you would stick a bunch of them onto some aluminum and use a diffusion layer to cover the seams. These things are expensive individually but you do see wholesale lots of around 150 iphone filters go for less than $150. Someone else can do the math on weather 150 iphone covers is enough for a decent sized screen.

From my testing, if you can get an image on a dark enough surface, the directional light rejecting component is less important than one might think. If your projector is bright enough, you might be able to create a back screen that does what you need for your room without the filters. If this is the case, you would be better off as you wouldn't have the viewing cone restrictions. This is my overarching point for this type of screen. Projectors are getting brighter. In a few more years, most people won't need directional light rejection to watch with the lights on, just enough contrast enhancement. I have a number of projectors including some bright pro devices for work. A black screen without the filter as shown in the tests is enough for most of the devices to work with the lights on. With sunlight, you need to the pro devices but with normal room lights, even when very bright, my home theater projector at 2000 - 2500 lumens works really well on the diy black screen. The dimmest 700 lumen device even works with a fairly bright room.

I am going to keep looking for suitably sized filters but I may just come to the conclusion that I don't need it when the new test screen material arrives for trials.

TBC
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post #5 of 439 Old 08-13-2013, 03:06 PM
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Hello New Design,
aka: DLU wink.gif

All I see happening is attenuation of light resulting in darker...everything.

http://www.avsforum.com/content/type/61/id/257628/width/500/height/1000/flags/LL

Such is the nature of all virtually all Grays, be they Tinted or Layered surfaces, translucent or wholly absorptive.

Also, it's very well known and accepted that with a Bright enough PJ, a virtually Black surface can reflect a very tenable image
The link below points to a half spoof , half serious look at Black Surfaces hit with a preponderance of Lumen output. Sadly, the images once on are gone.
http://www.avsforum.com/t/743468/breakthrough-in-ambient-light-rejecting-screen

Unlike the "Aluminum" crowd, one of the primary applications we advocate is Silver Fire, itself a Translucent medium saturated by Silver and Pearl components, and made to specific bshade of Gray via the addition of varied amounts of a RBGY derived Colorant. This allows for a far greater amount of overall surface reflectivity, combined with layered attenuated reflectivity, yet any overt tendency toward excessive reflectivity is held in check by balanced amounts of translucent Gray colorant.

This application had it's roots over Aluminum Sheets, Mirrors (Light Fusion) Brushed/Rolled/ Sprayed Silver Metallic, and currently over Bright White substrates..

Frankly, we bested the Sony Chroma View quite easily, based on a performance / size / cost ratio, and the Dyna Clear was never in the running, wasted as you say by SONY with undersized and ill designed application woes.

Films have been explored quite extensively, and the general consensus was the same as you have discovered to be true. Wholly impractical and cost prohibitive for the practical DIY'er.

Despite rebuke, denials, and attempts to discredit both application and creators, no other source, be it a Commercially available paint, or a competing "Forum" , has either posted comparative Screen Shots showing anything close to our results, nor has enjoyed the number of satisfied end users we have achieved...those who actually saw great improvement in both ambient light performance and enhanced viewing in dark Theater conditions. We are talking well into many hundreds...conservatively speaking, and that speaks volumes for any application constantly under Peer review for several years.

This with Paint...usually sprayed, but sometimes rolled,..and although we don't advocate rolling much, those who do roll don't experience the issues that crop up continually with "other" reflective paints.

Summed up, the SF / RS-MM DIY Screen paint apps are designed to provide maximum performance in "any" given situation due to their infinite adjust ability. And it's truly infinite...not just "adjustable" in a downward loss of "gain" due to attenuation by adding a basic neutral Gray to taste.

But that is SF, and what your trying to shake out is full of promise, if clarity, color correctness, and gain can be maintained to a point that any IQ losses are basically non-determinable. And that doesn't mean your app or any app needs to show whites as"Bright" as those off a 1.1 gain matte white surface. What is expected is that gain is not lost across the board, but rather Blacks get lowered a greater proportion than do Whites and bright colors. Gray scale detail in between should not suffer crushing. And it should all be able to happen using PJs of normal output of beyond 1800 lumen (...the lack thereof being the bane of the old Chroma View...)

Yours is a tough road to travel, but you won't find any lack of encouragement, nor any derisive but shielded commentary. This Forum doesn't depend upon the Moderators or Administrators to keep interest and traffic flowing. We members here do it via a honest effort to help as much as we can, knowing one person's success leads to others finding a similar path..

I'm not sure how much immediate interest your postings can generate, but on this, the World's largest and most respected A/V Forum, your almost assuredly going to have some success in finding those with not just a similar interest, but also the ways and means to contribute meaningfully and make your project a successful one. I hope it happens.....really.

But if not, slide back in and check out our DIY painted options, such as specialized coatings over 1st Surface Mylar, Mirrors (..yeah...Light Fusion...it works, don't let anyone persuade you otherwise...) and other really big ambient light resistant screen apps (180" to 230" diagonal)

To quote James T. Kirk;
"I'm laughing at the superior intellect"
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post #6 of 439 Old 08-13-2013, 05:24 PM - Thread Starter
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We'll see. I think this is a topic that has some general interest due to the hype and great marketing.

For me it isn't just about the best performing DIY screen (although that is always nice), this is specifically about making a DIY black-screen.

Part of this is performance but the other part is the aesthetics. Part of the appeal is the high tech look you get with the darker materials. I guess some of that is just taste. Given the size a permanent screen has in your room,referring the way it looks is also important.

On the mirror / Mylar thing, I am interested in their use as the reflective layer. They are one of those things that people have opinions about. Sometimes those opinions are formed after trying it. For a DIY screen, I can see there being a cost issue with buying a mirror that is big enough. I have seen some first surface mirrors that are light (through being glassless) that are reasonably well priced. I saw one that was 4 foot by 8 foot that came in under $400. Still, a lot for a DIY project, especially if I intended to paint over it. It also assumes I'm happy with the result which makes it more of a gamble. I have tried mirrors before with limited success but never a first surface mirror. I think we agree that it could do more than aluminum paint. Until I try it, I won't be in a position to say more.

Now Mylar is of interest due to the claims of 97% reflectivity. I wonder however If the fact hat it is secular reflection has an impact. Now I know you are using paint on top to diffuse the light but I wish I understood enough to know how a specularly reflective surface under the pant would compare to a diffuse reflective surface. I have seen some reflective aluminum that claims 94% diffuse reflection. The Mylar arrives in a few days. I'll post the results. I could see a layer of Mylar followed by tinted film followed by light diffusion film being a viable method.

The other methods I want to evaluate are aluminum sheet as you know and an off the shelf retro reflective sheet that also claims 97% reflection. The aluminum has the advantage of also being a flat smooth surface to attach other layers to and it is what the black diamond screen uses to keep it rigid.

I disagree with the point that with a bright enough projector, anything can be made to look good. I have experience with some fairly bright devices. I have done some work with barco pro devices etc. it doesn't matter how bright the projector, on a light surface, they all look washed out in a bright room. I have being using a grey screen for comparison to keep the test relevant. In a bright room I calibrate the projector for the grey screen or the lighter of the 2 to make it look the best it could possibly look before declaring any improvement with a black screen surface.

I know it is possible to sway the results if you want. I have tried to show that this isn't what is going on here. I guess the only way to satisfy 100% is to try it and compare the results to your current screen. I like to start by making the room bright enough to challenge the projector I'm using on the optimal settings, then see what a new screen can do.

I'm not 100% that films are the way to go yet but they are in the lead so far depending on what happens when the next lot arrive. They aren't as cheap as most paint (although many screen paints are unjustifiably expensive) but we have a different type of budget here. Normally, you compare the cost of a DIY screen to an equivalent or acceptable off the shelf offering. You can buy a ready made white or grey screen for less than $100 in some places. Here we are comparing it to black-screens that tend to start north of $2000 and north of $3000 for the size you want. I would say that gives you an extra couple of hundred in the budget to create a viable black-screen clone with a high end look. Especially if you want to use glass and aluminum like the high end screens. If one could make one that looked the part for $200 in parts, I would think that is still viable for some. If you want to make a screen for $50 in parts, there are some good options. Black widow screens are good in my opinion. But if it has to b black.... And black is the new black when it comes to screens!
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post #7 of 439 Old 08-13-2013, 06:51 PM
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Color me intrigued, looking forward to seeing your progress. As far as light diffusion goes, perhaps something along the lines of silk organza would possibly do the trick?

I love the idea of a black DIY screen, consider me rooting for you on this one.
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post #8 of 439 Old 08-14-2013, 04:18 AM
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Quote:
Originally Posted by New Design View Post


I disagree with the point that with a bright enough projector, anything can be made to look good. I have experience with some fairly bright devices. I have done some work with barco pro devices etc. it doesn't matter how bright the projector, on a light surface, they all look washed out in a bright room. I have being using a grey screen for comparison to keep the test relevant. In a bright room I calibrate the projector for the grey screen or the lighter of the 2 to make it look the best it could possibly look before declaring any improvement with a black screen surface.

You misquote.

I said that when using a "Black Surface", if you have enough lumen it can be made to look good. This of course applies to any dark Gray as well. If one's coating has a balanced amount of reflective elements, the amount of needed lumen output will drop.

White has never been right.....if contrast was to be considered. Only a PJ with 10,000 lumen output, and 10,000,000:1 "Native Contrast", shooting onto a 100" screen could ever hope to maintain decent Black levels under adverse ambient light conditions if such a surface was a "White" one. Not very practical.
Quote:
I'm not 100% that films are the way to go yet but they are in the lead so far depending on what happens when the next lot arrive. They aren't as cheap as most paint (although many screen paints are unjustifiably expensive) but we have a different type of budget here. Normally, you compare the cost of a DIY screen to an equivalent or acceptable off the shelf offering. You can buy a ready made white or grey screen for less than $100 in some places. Here we are comparing it to black-screens that tend to start north of $2000 and north of $3000 for the size you want. I would say that gives you an extra couple of hundred in the budget to create a viable black-screen clone with a high end look. Especially if you want to use glass and aluminum like the high end screens. If one could make one that looked the part for $200 in parts, I would think that is still viable for some. If you want to make a screen for $50 in parts, there are some good options. Black widow screens are good in my opinion. But if it has to b black.... And black is the new black when it comes to screens!

Gosh, I'm not sure why you seem to ignore all the work that has gone into proving both the viability and performance -to-cost that Silver Fire has provided, considering the literally thousands of posts on here about such.

You speak of cost comparisons...well any Silver Fire v2.5 4.0 of normal dimensions (98" to 120" diagonal) cost less than $250.00, including Substrate, Gun, & Trim. Yet they can and do perform well enough to make the expenditure of $3K for a BD a silly proposition....if one can indeed employ DIY methods

Also, the Black Widow apps are nothing but Gray Screens with low Gain characteristics, and were for a time made unique ONLY by use of a Beige Base that was color corrected by the use of Aluminum flakes. But they were nothing if not just gray screens with granular issues and frequent roller-based issues. Now that the formula for AAA Aluminum has changed, the BW genre is reduced to being just another version of what we have been doing with Mica based mixes on here for years, only it's wholly dependent upon just one reflective element. There is only one real reason that BW exists. It has to because it cannot be what SF is, or embrace the ideas behind SF, lest it be acknowledged by some that it was always the best solution. THAT won't ever happen "publicly"....only gradually and without any acknowledgement as to where the originating concept came from.

Frankly speaking, every aspect of what we have done is eventually copied or embraced by "others" out of necessity, not individualized creativity. Resistance to Reflective based mixes has been the domain of just a relative few, who have tried hard to dismiss such as being even acceptable let alone viable..It mattered not that hundreds espoused the quality and effectiveness of such apps, only the opinions of a few, supported by personal vendettas against such apps and their originators were to be considered "truths". In truth, it has always been about simple jealousy over the acceptance of certain ideas, and the amount of attention they get.

That's a very self serving and selfish way to approach DIY'ism. No...it's through Hard work, creativity, and the willingness to help "above and beyond" simply posting a SpectroGraph and ranting about other different options being inferior, all that is what determines how much confidence (...and appreciation...) is deserved.

On this Forum there is a tremendous amount of proven applications that show just how well advanced Paint Coatings can perform. They can be ignored by those whose agenda requires they be discounted, but as stated before, those individuals are very few.

Basically, comparing BW to Silver Fire is no comparison at all. That has always chapped a few Hind Ends. The amount of Aluminum cannot be increased without creating a myriad of issues. The gain can ONLY go down as more Neutral Gray is added. And all the application woes still remain. Not to say that Silver Fire doesn't have it's own application considerations, but in SF's case, the performance gains easily make such considerations well worth....well, considering. wink.gif

Mirrors. Well, much effort has been ladled onto their use. 1st Surface Mirrors "seem" to be the most practical answer, but they are not. 1/8" 2nd Surface Plastic Mirrors were, and have always been the practical application....and the performance they allowed always made the expense worthwhile. For a goodly spell, Silver Fire Light Fusion was the "Go To DIY App" for those who aspired to something really special. But supply of decent sized Plastic mirrors has been curtailed, (...since 2009) leaving only 98" diagonal and below sizes practical in the affordable sense.

It was that development that led to a change in Silver Fire so that it could be readily employed onto Bright White surfaces and still provide a similar degree of reflectivity. Other 1st Surface substrates such as aluminum (..,brushed or polished...) sheets, Mylar, or similar glossy reflective surfaces still require that a high percentage of their reflectivity be masked by the translucent coatings, so much so that they can provide nothing much more than a very subtle "contrast oriented" effect due to a general darkening of the topmost reflective surface.

Your use of Films over such surfaces is the same approach that Screen Mfg use / used, and was / is the reason so many discounted the possibility that such an effect could be duplicated by DIY paint. It was in fact a challenge set before this Forum (...circa 2004...) to duplicate the Sony Chroma Vu with paint that got it all started. So...in the long run, what really needs to be ascertained is as to if such a "Dry Film" layered approach can be made both financially viable, and practical as relates to DIY work ethic and ability. It was well known that it "could be done" back in 2006, it was simply not financially feasible, that's all.

When I consider your idea, I see the use of a diffusing Film over Mirrored Mylar, sandwiched between two Substrates. A stiff rear board, and a topmost layer of optically clear Acrylic just 1/16th" thick as being a advisable choice. However that is essentially a Vutec SilverStar, so it's nothing new. Besides, the Silver Star was more about directional gain than it was about maintaining Contrast. Much the same as a DaLite High Power is.

My own experience with all such apps has shown that if they are to maintain gain, they will have hot spotting issues. If they use a brushed or powdered aluminum substrate, they will exhibit graininess. To my reasoning, the right highly reflective "ultra smooth Painted Surface" that would then employ a specialized Film as a top layer would seem to have great promise.

Something you might want to consider.

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post #9 of 439 Old 08-14-2013, 04:24 PM - Thread Starter
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Not ignoring the work with mylar. Infact, it is one of the things I was / am waiting to try and my mylar sample was among the goodies that got delivered today.

I have never worked with mylar before although looking at it now, it seems similar to the mirror tinted window film I have tried. More reflective maybe. It looks different to how it behaves in a way I don't really understand. The surface looks like a mirror but it is also a little see through. The reflection is nothing like a mirror. I am not sure if there are multiple types of mylar (other than thickness). Here is a pic of the one that came and the reflection from the projected image. A mirror would reflect a watchable image, the mylar reflection was somewhat more diffused.




One of the things I like about films generally (for painted screens) is that the surface is smooth so you end up with a nicer painted layer on top. For the tests in the following pics, I tried both mylar and a matt aluminum plate to see the difference. Although the purpose of these tests was to find a good diffusing and tinted layer for the front surface, It is also useful to try a few different reflective surfaces to see what works. I was pleasantly surprised with the test films. These were not the ones I had the highest hopes for. Instead, I think I found some viable options that offer both tint and light diffusion with no hot spots.

Specifically, this dark grey film. It has a matt finish on one side and a glossy finish on the other. I projected onto the matt side and saw no hot spots from any angles which is a goof start. Here is a pic of the film. I have some darker films coming but this is the darkest for today. I tried it with just a reflective surface behind it and with some additional tint.



Here is what is looks like with a piece of aluminum behind it.



Not very black diamond 0.8 gain. Perhaps somewhere between the BD 1.4 and 2.7 colors but still looks kinda flatsecreen TV-like with the dark tint over metal.

I also tried it with some additional tint and it looked much closer to black:



Before I show the results of my very crude initial tests, here is a pic of the comparison screen:


This is my white wall screen, not the normal grey screen I use for comparison. It's a tough day for the white screen. The angle it is at makes daylight stream in from the side washing out one side more than the other. I would probably never try to watch like that with any screen for uniformity reasons. Dealing with light is easier if the whole screen is equally impacted. The projector in use is 2500 lumens. Today is less about ambient light capability and more about finding a front layer that is smooth like a film but doesn't hotspot. The other layers will take care of the light (hopefully!). Ok, here is a shot of the result: The first one is with just the film and aluminum plate behind it. I like it!



It's hard taking pics when it's just me on my own but from my seat, I was really please with how it looked. I couldn't make it hotspot from any angle I tried. It made me smile. Here is a pic using mylar as the reflective layer:


Bottom line is that the mylar works as a reflective layer. It is far harder to take a picture of in a crude test though. It wrinkles easily with a slight finger movement and if it isn't 100% smooth, the creases are visible through the film and cause a shimmer. Now, if I used Mylar instead of aluminum, I would need to find an alternative rigid surface to attach it too. I am assuming that once attached to some wood or plexiglass, this wouldn't be an issue. Mississippi Man (hope I spelt that right!), in your experience, what is the best way to attach mylar to a rigid surface? I have various types of glue and resin. One of the things I found with other mirror type films was that they are the only thing that epoxy resin doesn't stick to. Does it need a specific type of glue?

Here is a pic at the right angle of the grey film with a privacy filter behind it and aluminum behind that. The privacy filter is for extra tint for those who like a really black "black-screen". From the front, it actually works well.


From the side, the privacy filter blocks the reflectivity of the aluminum and the image goes dark:


Now one could ask the question, "what is the point of testing the privacy filter when you can't find one big enough?". I decided that if these filters were used as a second layer, multiple filters would be attached to the reflective layer and the seams would be hidden by the top layer. I actually tested this theory. Don't laugh at the following pic!



I can here you laughing!

Now, i am not sure I would recommend the privacy filters unless you are determined to make it reject light from the sides and above. I happened to get lucky on an ebay auction and got 50 iphone privacy filters for about $20. I don't have an Iphone so I could use them all for testing. With a little luck and a determined DIYer, a decent sized version could be made for less than $100 - $150. If anyone wants to go that route, I would suggest going for the older 2 way privacy filters and choosing to reject light from either the sides or above. I found that doing both gave me a viewing cone that I wasn't happy with. The other thing I would say, is that some are darker than others and some have a more regular shape. Go for the lighter ones and avoid ones where you will have to cut off too much of the filter to give you straight even edges.

Here is a pic of the grey film with aluminum backing and regular window tint added behind it:


I took this pic from the washed out side of the screen where there was the most direct sunlight. I want to repeat that test when I get some new tinted films. I guess the overall comment is that individual will need to select the type of tint based on their preferences and how bright their room it. The other point is that a darker tinted film can be balanced with a lighter front film (again based on preference). People with a really bright projector may want a 50% tint vs a 70% for a regular home theater projector. The other aspect is the reflective layer. The mylar was a little brighter than the matt aluminum and could therefore stand a slightly darker tint. With a polished aluminum surface or even a glass bead surface, it could be different again.

Here are some other films that I tested today:

More for comparative purposes, this is a relatively inexpensive front projection film. Not massively relevant to this except as a baseline for me.


This one is similar to the grey except a lighter shade. It is creatively called "light grey"



Over aluminum, it also has that plasma kind of look:


More BD 2.7 than BD 0.8. It would need a darker tint to get a blacker appearance.

The next one is a frosted film with a matt side. To get a black-screen appearance and effect, it needs an additional darker tinted film underneath but it works well like that.



Here is a pic of the frosted film with a light tint underneath and aluminum under that. It can go to dark grey with darker films although, if darker is the preference, I think the dark grey film is better up front.


I did also try a transparent film and it didn't work for me. Even on the matt side, I got hotspots. Not much use for a black-screen anyway but here is a pic of the problem just so you can see.



Here are some of the results. I have loads more pics but I'm limited on time right now. I can post more later:

Light grey with aluminum back


Frosted film with 50% tint and aluminum. My hand is there because if it is not touching all surfaces, the images gets distorted (one reason why I need an assistant!)


The surprisingly good front projection film - almost like a disposable silver screen.


The dark grey film use for rear projection - I always like the way that looks. Shame i don't have the room for it...


This is a completely different rear projection screen with an ultra short throw. This screen is a light charcoal and in my opinion, doesn't work as well as the darker film pictured above for the black-screen experiment. Still, a useful comparison.


I know these are all crude and I will do more testing to see. I just couldn't wait once I saw they had arrived! I have to go now but I'll post more pics later on or tomorrow. I have some new films arriving either tomorrow or the day after. Specifically, there is a dark grey (nearly black) material that I have high hopes for. I will upload some video clips too. They seem to be better than stills for showing this kind of thing. I'll keep you posted!

Does anyone know why a fabric being black reduces the viewing cone? Or if the same applies to really dark grey?
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post #10 of 439 Old 08-14-2013, 05:12 PM
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Excessive light absorption / attenuation doesn't allow for much dispersion off axis.

Use Mylar obtained from a Hydroponic Store...(98% reflective ) and ask for /get a thicker Mil. Besides being virtually opaque, it's stiffness will help avoid surface deformations and creases and make fabrication handling easier.

Deja Vu, ya all. tongue.gif
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post #11 of 439 Old 08-15-2013, 05:54 PM - Thread Starter
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My light diffusing samples arrived today. These are from a company that makes light diffusing films specifically for the display industry. It's amazing how products that look identicle have different names and price points depending on what it's used for and the perceived value. These sample are not too different from the significantly more expensive rear projection window films I've used in the past. I got sent a folder full. Apparently every variation this particular company makes although at a high leve, there are 2 kinds.these are: single sided and double sided diffusion. The rest were all versions of one or the other but with varying thickness. A slight increase in thickness means a slight increase in price although there doesn't seem to be a huge difference between the best and worst with regard to price and functionality. I'll get some pictures up in a bit but net net, they work really well. In fact, they work so well that I would say I'm done with my search for my first layer of the black-screen. I did have high hopes in anticipation for this lot given the specialist purpose of their manufacture and the very reasonable pricing I was sent ahead of time. Sometimes these things are totally out of line with a DIY project when it comes to price. A 50 yard roll of this stuff comes in well under budget.

I did some quick testing and single sided seems to work just fine for this purpose (perhaps even better) as long as you use the Matt side. Both were hot spot free. Two layers of diffusion gave a lighter appearance which is fine if you aren't bothered about making the blackest black screen. The single sided diffusing film is far more transparent so placing some dark tint behind it gives you a very black diy black screen. Both give an amazingly smooth projection surface.

One of the main purposes of these films is even distribution of light so it seemed to also give a fairly broad viewing cone. I don't want to speak too soon on that given how quick and basic the initial test was. I am going to order a roll as soon as I have gone through each sample to choose the best for my needs. Then I'm going to build a working prototype. My large roll of tint arrived today too that just leaves the reflective layer.

I just ordered another reflective film randomly. This is a film that claims to be diffuse reflective covering 97% of the visible spectrum. Also like every growing reflective film, it claims that the other kinds make false claims about how reflective they really are and that others barely scratch 80%. Who really knows????

I was thinking about that... Just because something reflects 97% of the visible spectrum, does that mean that another material, that also reflects 97% of the visible spectrum, can't be more reflective. Ie both cover the same spread of color but one does it more intensly? My initial read was that the 97% was a measure of the intensity but then when I use it and don't get the 7 gain screens claimed by some of the commercial options, there must be more too it.

The Elite Starbright7 for example has a gain of 7. I am assuming there is more to that then a piece of growing film under some grey cloth?

One last thing, I got a call from a company today claim to off micro louver film that is large enough for a DIY black-screen. I had almost given up on that. I will report back if they can do them at a price that works for a DIY job. Given how much the small ones are I am not too hopeful on that. If anyone works for a printer, please let us know if it is something than any printer who can print on transparent film an do?
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post #12 of 439 Old 08-15-2013, 08:01 PM
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Very intriguing, looking forward to the pics/video. Sounds better than silk organza, lol.. I'll just leave this one to the experts. smile.gif
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post #13 of 439 Old 08-17-2013, 02:44 PM - Thread Starter
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As promised, here are a few pics from initial testing of the light diffusion material. As a case of good timing, the black screen fabric I had been waiting for also arrived so I will show both as these are the ones I will use to make my diy black-screen. I am happy enough with the results not to need to try anything else for now.

First, here is a pic of the black-screen material:


As far as usable screen materials go, I'm sure you'll agree it's about as black as they come. You could just use a material like this on it's own as a rear projection fabric and it your room allows for that, it isn't a bad option for both beating ambient light or just giving you the best blacks in town. Here is a pic taken of it being used for that purpose during the day with the blinds open:


I actually have a couple of ultra short throw projectors and I would be tempted to create a rear projection screen if I had no luck creating a front screen. It is certainly the easiest and cheapest diy black-screen option I have been able to make work. To make it into a usable front projection screen, it needs a reflective non-see-through layer behind it and a light diffusing layer in front. This particular material has a matte side and doesn't hot spot without a separate light diffusing layer but the diffuser will do more than just stop hot spots in this case. It also adds brightness and uniformity. Here is a pic with the black material being used as a front screen surface with just aluminum behind it:


Now I'll try and show the results for the next bit as best as I can but I will say up front that it isn't the easiest thing to photograph well and in a way that captures how it looks in person so I will add commentary where needed. In addition to me trying to take pictures on my own with a phone camera, I have sunlight shinning into the room and the lights on. deliberately difficult conditions for the screen but also for the camera. Just using the material and aluminum works but the brightness suffers somewhat. It is fas more watchable than my white screen under these conditions and I may even settle for it if I didn't know any way to fix it. This is where the diffuser film comes in.

I was very kindly sent a range of different types to try because I didn't really understand how to select one over another. Here is a pic of the range that was sent:


At a high level, there are only 2 kinds though. Single and double sided. Then it is just a case of different thickness of substrate. The most expensive is the thickest double sided version and the cheapest is the thinnest single sided version. The typical use for these particular ones is for LCD screens which gave me some comfort that they could work for projection screens (although there is no basis for that comfort). In terms of functionality, the greater thickness and extra side will give you greater light diffusion. For the black screen project, the trade off is in appearance. The thick double sided films look very white and you would end up with a mid-dark grey appearance over the black fabric. Here is a pick of the most expensive one in the pack:


For our purpose, I didn't find the thicker double sided films to be necessary. The thinnest and least expensive film took care of hotspots and uniformity just fine (for my tastes anyway). That statement is true for both front and rear projection btw. Even the most transparent version eliminated hotspots for direct rear projection. Here is a pic of the one I ordered a roll of for my screen:


While it looks far front 100% see-through, if you hold it in front of your tv, you can see a fairly clear image through it. I couldn't even begin to explain why. Importantly it doesn't significantly change the appearance when on top of the black screen material. I think that the blacker appearance gives darker blacks when the screen is on but it is important that the screen appears black when off too as it is a "black-screen" after all. Here is a pic of my chosen diffuser over black material and aluminum:


Selecting the right diffuser/fabric combination will be about the users preference on aesthetics in some part. This method also works well with dark grey fabric or silver. You could get a perfectly watchable and high gain screen by just laying some diffuser film over some aluminum sheet. One thing to be aware of, is that using a non-matte layer under the diffuser may be problematic for the thinnest top film. I say "may" because I didn't see this until I tried a particularly glossy window film under the diffuser and I felt that it would benefit from going up 1 or 2 thickness levels. For this reason, it is worth trying a few diffusers if you want to use very glossy screen material.

Here is a pic of my chosen materials in action. Now this is where I start to have trouble with the pics. Holding 3 different materials straight with one hand while trying to take a pic is hard. A light space in between layers give distortion. I will post better pics when I have finished making a full size screen but for now, we'll have to make do with the sample sized material I was sent:
AppleMark

AppleMark

AppleMarkAppleMarkAppleMark




With the diffuser, the image is a lot brighter. Remember, in the pics, the room is very bright. Sun-light and room lights from all directions. I should post some pics at night with just room lights too as that is likely to be closer to reality for most (including me). The uniformity the diffusing film brings just makes the image look right. Like the difference between a pro screen and one I made in my living room perhaps. In future, I think I will add a diffuser film like this to any screen I make. The smooth film gives a really sharp image. Easier to appreciate high definition images of a smoother surface and this is the only way I have seen of getting a surface this smooth without major hot spots.

For the finished screen, I intent to get a piece of aluminum sheet and stretch the black material over it along with the diffuser film and stick both of them with glue around the back to create an edgeless screen. I know the idea of not having a border is sacrilege to some but I think the black material can get away with it. The other thing I am considering is adding a thin sheet of glass or plexiglass to the front and sticking the diffuser film to that to stop hot spots. That would give it that high end plasma look. I may even finish it with a layer of carbon fiber on the back to cover where the material is glued to the aluminum. Using the above method, I believe my diy black-screen will end up costing about $150 for a 120-140 inch 2.40:1 screen. It could probably be done for a lot less with cheaper materials and by using the wall as the rigid layer.

I also think it is possible to find something else for the diffuser layer that could be even cheaper. I haven't tried it but a matte light diffusing frosted or etched window film could work. They exist and can be relatively inexpensive. The key is getting one that is matte. I have no idea if it would work as well as the ones I am using but I see no reason why not. Then again, I have no idea how they work so I'm not the best person to ask on that last point.

I know it's hard to form an opinion from letter paper sized samples so I will definitely post pics and video clips when my roll of diffuser film and aluminum sheet arrive. I also tried it btw with a larger privacy screen from an lcd monitor. With the diffuser film on top, it functioned just like a high-end directional light rejecting screen. I managed to get a wholesale lot of 20 inch filters for $80. Enough to make an 80 inch screen to try. With the film on top, you wouldn't see the seams. If that experiment works and can be made to look ok, I will post some images of that too. That would be the last component of the diy black-screen. Making it reject light from the sides at diy pricing would be a result. As the zen master says "we'll see".
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post #14 of 439 Old 08-17-2013, 04:01 PM
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By all means, get a full sized (...or sizable...) stand-alone example worked up and place it so we can indeed see the degree of light present, and how it is /isn't affecting the image quality.

That means shots of the entire screen, and a goodly amount of room area surrounding it as well.

Good luck with your fabrication efforts!

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post #15 of 439 Old 08-17-2013, 04:12 PM - Thread Starter
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A couple more pics for comparative purposes.

Here is a pic to try and demonstrate the importance of the diffuser film. The right part of the hunger games image is covered with the film and the left part isn't.


The lift in brightness and uniformity is more noticeable in person although you can see it in the pic too.

Here is a pic with a completely different type of diffuser material. Ultimately I declared this test a failure because the material was too thick and too expensive. While it gives an image and that image is better than the white screen, it adds too much white to image for my taste. The loss in contrast is noticeable. You could still watch in these bright conditions but you wouldn't be thinking that it is just as good as with the lights off:


With the thinner (and cheaper) diffuser, the perceived contrast is just better. This diffuser is basically colorless and leaves the screen looking black while giving uniform brightness.



And again without:


If you have a very dim projector, consider using a thicker diffuser layer before looking for a brighter reflective layer. This black fabric has a very low % of light transmission (how much light it lets through). A brighter layer behind it is unlikely to make a huge difference. A thicker diffuser will sacrifice some contrast and black appearance but give back some brightness. I did my tests with 2500 lumens and the brightness at half way and it was plenty bright enough with the thinnest most transparent diffuser and the blackest looking screen.

If you have one of those older 500 lumen projectors, it is worth doing some tests before you go with any kind of black screen. I would say that in the tests I have done with lower brightness projectors (700 lumens), I haven't had any problems. Normally brighter projectors sacrifice blacks. With a black-screen, it feels like the best of both worlds as the perceived contrast shoots up. Even with dimmer projectors though, the helping hand on contrast feels like it makes much more of a difference that just adding gain alone but I guess it will depend on what type of content is being shown to some degree.
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post #16 of 439 Old 08-18-2013, 01:45 PM - Thread Starter
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While waiting for my diffuser roll to arrive, I couldn't resist cutting a piece of the black fabric and doing a test with a different diffuser material. The diffuser used here is a little too thick and both are only pinned behind some foam board without a reflective layer but it still made for an interesting test.

It looses some brightness without a reflective layer but is still watchable in a bright room. It shows what a difference contrast alone can make. I wasn't going to cut the black material because I want to use all of it for my screen but I decided I could spare a little in the name of science. The white screen used for comparison is about 100 inches. The projector is calibrated for use with this screen as it's what I use to watch movies on (although normally in a darker room). It is a 2500 lumen projector. I use that movie "The Hunger Games" a lot for testing because it is on Netflix, is 2.40:1 so I can see how the black borders look and it is full of fast dark scenes that challenge the screen. On the black-screen tests that didn't work, this movie was too dark to watch. It is still a little dark without the aluminum behind here it but still watchable even with the bright room. The clip also shows where the brightness is coming from. In this case open blinds during the afternoon and room lights overhead.

http://www.youtube.com/watch?v=0v-brk00Ty4

Here is a pic of the diffuser I am waiting for:

AppleMark

You can see how transparent it becomes for the surface it is touching. The diffuser in the video clip is also somewhat transparent but it's a lot thicker and more expensive.
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post #17 of 439 Old 08-18-2013, 02:16 PM - Thread Starter
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Check out this clip with the diffuser film on a mirror. You could make a very bright screen with just this - similar to the silver fire screens made with paint. I think this is a good demo of what the diffuser does as this largely transparent film changes the specular mirror reflection into a diffuse reflection that could be used as a screen.

http://www.youtube.com/watch?v=gzPOBr5zdfY

The obvious issue in the clip above is the lack of blacks for contrast. This can be fixed by adding a layer of tinted window film. The darkness of the film can be chosen according to taste. The darker window tints seem to work fairly well for a black screen as long as a decent diffuser is used.

I'll take some footage of the same test with some window tint in a bit.
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post #18 of 439 Old 08-18-2013, 03:01 PM - Thread Starter
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Here is another clip using my chosen diffuser, my chosen black fabric and using a mirror as the reflective layer. The clip starts with no diffuser layer, just black fabric on a mirror. One of the issues with using a mirror as the reflective layer is the difference in brightness between watching from the center and from off to the sides. When in the right position, it looks super bright, when off to one side the image looses brightness quickly, especially with the black screen material. You can see this loss of brightness in the clip. Watch the difference when I add the transparent diffuser film. The more uniform brightness seems to light up the screen area it covers. For fabric this dark, it makes the difference between it being usable and it being too dim to tolerate.

http://www.youtube.com/watch?v=Zi89xCun84U

Interestingly, using a lighter (although still dark grey) material over the mirror, exhibits the same issue. Changing the mirror to a more diffuse reflective layer and changing the fabric to a charcoal grey does widen the viewing cone or at least make the spread more even. I find that just adding the diffuser layer up front has the same effect. Perhaps even better. I could see the image well enough from the sides.

I'm going to post another clip in a bit which shows the diffuser over near blackout glossy window tint. Again a mirror is used for the reflective layer although that should make no difference as the tint lets very little light through. The clip is of interest because it works fairly well too. Perhaps the glossy tint acts like it's own mirror and the with the light diffuser film to eliminate hot spots it reflects enough. I don't need to understand why exactly but the key point is that with the right front layer, you might be able to get away with any inexpensive black material as long as it lets some light through or has some reflective properties of it's own.

I also had very good results with just a tinted diffuser film and the mirror. It was far more BD 1.4 (in color) than 0.8 but it still looked suitably plasma-tv-like. I'll put up some more clips in a bit.
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post #19 of 439 Old 08-18-2013, 03:07 PM
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Very interesting!

Looking forward to see a bigger prototype. Also see some pics/video using a PJ with lower lumen, around 1000 if its possible,
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post #20 of 439 Old 08-18-2013, 03:53 PM - Thread Starter
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Here is a clip showing black-out window tint on a mirror with diffuser. The mirror will make little difference here because the black-out tint lets very little light through.

http://www.youtube.com/watch?v=x8XJ1BDp_TY

The tint is glossy enough on its own to generate some reflection with the diffuser film although not nearly as bright as when the mirror can give it a helping hand.

I will post another clip in a bit that shows the same test but with a 70% tint. The brightness increase is huge. The mirror and diffuser film give it near led screen level brightness. Almost like its back-lit. It's uploading now so I'll post in a bit.

This more expensive tinted diffuser could eliminate one of the layers. It's not that black in appearance when held over mylar but it is fairly dark.



With some glass, it would look flat-screen-like. It gives a good image with the mylar behind it too:


The same materials on a mirror instead of mylar gives a noticeable increase in brightness.


I can understand why Mississippi Man is so passionate about the silver fire screens. From the right angle, the have a back-lit look that makes them seem more like a commercial screen. Mirrors have the added advantage of being easy to stick tinted films to. They can also be framed to look like a plasma. I am tempted to search for one that is big enough to go under my black screen material at a price that is worth it for DIY.

I have seen the acrylic mirrors on ebay for fairly little money but I don't know how they compare to glass mirrors or the high end first surface mirrors. I have some polished aluminum coming to try first but if I don't get the results I want from it, I wouldn't be unhappy with a hybrid silver fire / black-screen design and positioning my projector and screen at eye level so I can sit in the bright spot.

More clips uploading in a bit
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post #21 of 439 Old 08-18-2013, 04:05 PM - Thread Starter
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Clip with 70% window tint on a mirror with diffuser film:

http://www.youtube.com/watch?v=G1xs6xEmk7Y

Note, a problem with this combo is air bubbles. These come out eventually but it is hard to build a screen for use right away when using self adhesive films. I find it almost impossible to avoid air bubbles with multiple films and they take weeks or sometimes months to come out completely. You can see some of these bubbles in the clip from just placing the films together lightly.

Here is a clip with 50% window tint over mylar with light diffuser film over that. It works fairly well. I prefer a darker look but I do like the way this combo looks too. I would see it looking nice with the diffuser film attached to some glass as the top layer with the tint under that attached to the mirror or mylar. It would look very plasma-like.

http://www.youtube.com/watch?v=OM789U_01Kc

Note the changes in brightness with different angles in this clip. Depending on how bright you want it and how bright your projector is, this may be a good or a bad thing. If you want to squeeze every ounce of brightness from your setup, strongly directing the light into a narrower cone might be preferable. As my screen and couch are on the same level all the way across, it would work very well in my room.
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I can do that for you no problem. I have a 700 lumen projector. I will take some clips for you and upload them in a bit. I don't know if you saw or not, but I posted a clip on my youtube page with a 700 lumen projector for one of the earlier prototypes?

It worked a lot better than I thought it would. I'll get some shots and see if this is the same. If it isn't, I'll get some shots with the other diffuser materials for you. If the darkest combo doesn't work well at that level, I am certain a slightly thicker or double sided diffuser will make up the difference. I'm not sure it will need it though. I am 75% sure it will work fine. If not, I will put on my orthopedic shoes and stand corrected.

What kind of projector do you have if you don't mind me asking?

It's a shame, I used to have a 200 lumen projector but it broke. That would have been a difficult test.
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post #23 of 439 Old 08-18-2013, 07:12 PM
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What do you think using high gloss black paint on a wall (like piano black) and put a light diffuser film over that?
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post #24 of 439 Old 08-18-2013, 08:08 PM
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Igreis asked the question I was quietly pondering.. That light diffuser film seems to be some very interesting stuff, making me wonder what else it could work on as an outer layer.
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I have a VW95. Its around 700-1000 L depending on mode.

My interest here are the black level and also lowering reflections on wall/ceiling/floor. Ambient light capability is not a problem as I watch movies when it's dark.

Today I use a draper react. But better blacks is always nice.
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Quote:
Originally Posted by lgreis View Post

What do you think using high gloss black paint on a wall (like piano black) and put a light diffuser film over that?

It depends on how bright your projector is and how thick the diffuser is but as a general rule, I would say that method would be missing the reflective layer. Black paint tends to not let any light through at all. You might catch some reflection off the gloss but most of your image would be coming from the diffuser film. I think you'd have to use a double sided diffuser to get a watchable image and the end result would look more dark grey than black.

If you want to test the paint, put some on a piece of plexiglass or something else transparent and hold it to the light when it's dry. Most light paints will let light through. Black paint normally stops all light with one coat. It you thinned it with water, and added a reflective layer under it, that might be better. You can get tinted window film relatively cheap though and it would make it a lot easier for you to keep it uniform. The early tests I did were with paint and I used black paint with a translucent layer on top. I posted some clips of this in my earlier posts. That worked but it was really hard to get a smooth uniform surface. I had to buy a paint sprayer. A combo that I had some luck with was black paint mixed with aluminum ink. The ink had enough saturation to give me a life in gain, even when mixed with black. Aluminum paint just turned the black into a similarly non-reflective dark grey. I got the aluminum ink from an art shop in the screen printing section. It's expensive but goes a long way. If it has to be paint for the first 2 layers, I would add a layer of aluminum ink, then watered down black, then the diffuser film. I would experiment with a few different top films until you're happy.

To keep the layers separate and to test of much light the black layer lets through, you could paint the aluminum on the wall and the black on the film. You can then hold it up to the light to see if light passes.

I guess that is a long way of saying that you could probably make it work. I don't mind trying it for you when my roll of diffuser arrives in a few days.
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post #27 of 439 Old 08-19-2013, 02:53 PM - Thread Starter
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Quote:
Originally Posted by Eternitay View Post

Igreis asked the question I was quietly pondering.. That light diffuser film seems to be some very interesting stuff, making me wonder what else it could work on as an outer layer.

The film I was testing is made specifically for lcd screens. Some are made as window films, for photography and growing plants. Any application that benefits from hot spots being turned into an even uniform spread of light uses them. Looking at other samples I have been sent, it seems identical to some of the rear projection films I've used in the past (although a lot cheaper). There is a huge variance in price for this stuff depending on who makes it and what the intended use is.

When I was researching the screens from the high end commercial screen manufacturers, there were a few cases where they showed high level diagrams of their "multi-layered screens". In most cases they are very secretive but all seemed to show a diffuser layer in there somewhere. They also show a tinted layer too. The more complex ones have more complicated fresnel lens arrays and light blocking layers but they are harder to acquire in the sizes we need without spending big bucks. Diffuser, tint and reflective sheets are all freely available though.

Any screen needs a diffuser layer. DIY screens normally use paint but you can use this film as the diffuser layer instead for any type of screen. As I show in the clip, you can make a version of the silver fire screen by just adding it to a mirror.

For any painted screen, adding it to the front can give you a more uniform brightness and smoother appearance. As 4k and 8k projectors come into use (if they ever make any consumer content), smoother screen surfaces will be preferable. I think that just that improved smoothness alone makes a huge difference over my diy painted efforts (although that says more about my diy capability than anything else).

I have a piece of anodized aluminum. adding the diffuser to that creates a really bright screen that is almost led tv bright. It looks kinda back-lit. It is definitely useful stuff to a screen maker as the most reflective surfaces often have a potential hot spot issue. a key advantage over paint is the amount of light it lets pass. With paint, you can start with a really reflective layer but by the time you add paint, most of the gain is lost.

Just avoid the overpriced rolls from brands like 3M who charge $800 for the roll. $150 got me enough for 6 huge screens and I didn't choose the cheapest option by any means.

It is best to get them to send you a folder of samples like I pictured so you can experiment and find the one that you like best.
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Quote:
Originally Posted by Johnrecon View Post

I have a VW95. Its around 700-1000 L depending on mode.

My interest here are the black level and also lowering reflections on wall/ceiling/floor. Ambient light capability is not a problem as I watch movies when it's dark.

Today I use a draper react. But better blacks is always nice.


If you only watch in the dark, I am not sure I would recommend the darkest black-screen as the best option. While great in a light room compared to a white or grey screen, it has some limitations like a reduction in viewing angle that you don't need to put up with if you only ever watch with the lights off. That said. I understand the black quest as someone who shares that interest.

I got similar results without some of the limitations by using a dark grey or charcoal material instead of black. The actual look of the finish is not too different by the time you add the diffuser. If you read the reviews of the Black diamond (for example), they all agree that it looks better than their comparison screen with the lights on but then not as good with the lights off. There is a reason why the BD 1.4 is more popular than the 0.8.

Check out this pic of the dark grey material with a diffuser over it. (this diffuser is thicker than the one I will use so actual performance will end up better). Even with the wrong diffuser, the screen still looks fairly dark or black-screen like.



When I turn on my Sony Blu Ray, the menu screen has a black background like the playstation 3 one. Here is a pic comparing the charcoal grey screen and diffuser to a white screen with the lights on:
AppleMark

As you'd expect, you get better results with the darker screen as the best the white screen can do is a washed out grey. The dark grey screen does almost as well as the blackest material and still looks the part.

With the lights off, you would expect the white screen to make up some ground and it does look better but the charcoal screen and diffuser still looks better overall.
AppleMark

I don't know how to measure it but it does seem to reflect less light onto the walls too. I'll experiment more when it gets darker outside.
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Thx for the pics. what kind of dark fabric were you using there?

Also, the louver mtrl seems interesting. Im thinking that if it works properly, one would not need to darken the screen that much as the sec reflections are the ones messing up the blacks in the first place.
I have a really bright living room, even the carpet is white:)

Maybe it could be used as a first? layer on a white/grey screen?
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post #30 of 439 Old 08-19-2013, 04:42 PM
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What do you think of using black widow paint mix with the light difuser film? The black widow ultra uses auto air aluminium fine with white or grey paint in 4:1 (4 white or grey: 1 aluminium) but we could use 4:2 for exemple to use more aluminium and had more gain and make a more dark grey?
Or in a dedicated theatre using with only a white paint screen to treat the secondary reflections?
What is the diference of using a thicker or a thiness light difuser film?
Thanks for the hard work
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