DIY black screen tests - Page 3 - AVS Forum
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post #61 of 516 Old 09-19-2013, 10:52 AM - Thread Starter
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Here are some more pics:

First, with black paint first. You get a darker appearance.



Much closer to the black-screen appearance we are looking for right? The reverse looks like this:


The results were impressive:


I like to look at the red Netflix banner as it always looks wrong if the material isn't reflective enough:


One more:


For comparative purposes, I painted some of my own home made grey screen mix which is made from titanium dioxide powder, treated aluminum powder, aluminum ink, 25 micron glass beads, black paint and water. This is my new favorite paint since it stopped being possible to make the old recipe black widow. It is many times better then the uber expensive commercial screen paint mixes. Here is what it looked like when painted on the back of the diffuser:



In the bright room, it looked ok, but not nearly as good as the darker black paint mixes:




The pic above has rgb glass on the front and black on the back. It was a lot of effort but it did look nice!


The pic above shows a multi layered mix with my screen paint, black paint and aluminum ink. Here is how the material looked:


All variations of this performed better than one would assume considering the dark appearance. I think the key is having a separate reflective layer and keeping the dark layer thin enough to let some light pass. If you really want to use paint instead of ink, you don't need to find water based aluminum paint like to have to for black widow as you don't need to mix it with other paint. Also, oil based aluminum paint is easier to find and considerably brighter in my opinion.


This one shows the black paint mixed with the aluminum ink (instead of separate layers.) Instead of turning grey, this gives a metallic black or charcoal appearance. I added a separate aluminum ink layer as well:


The last one shows the results of that mix which I think was the best variation in this sample set. I tried adding some glass beads to the mix and it gave a noticeable enhancement from dead center but didn't have the normal limitations of glass bead screens when off center. I plan to do more testing with this.

Anyway, I said I'd try to create a black-screen with paint and diffuser and there you go. It is possible. It isn't as good as the material versions but it is possible to create a good looking screen. Using the diffuser layer as the primary screen surface gets over many of the disadvantages of the painted screen in terms of the overall finish. With paint on the back, as long as the coating is even, the front looks smooth and professional. Not quite as dark as the fabric option but still, far darker than any paint only screen I have ever seen. The double sided diffuser gives enough white translucent screen surface to not shift the colors in unsightly ways or kill brightness. It is transparent enough though to let you retain that dark high contrast look. Also, painting on the diffuser saves you having to explain to the wife why you had to paint her living room walls black. The next question is, given how cheap fabric options are, do you really need a painted option?

Worth noting, I only tried this with aluminum ink, not paint so I am not certain it will work as well. I'm not certain it won't either. As an FYI, I used a standard black semi gloss paint and Speedball water soluble silver screen printing ink which I purchased from a local art shop for $7. It can be purchased on Ebay too. I would buy 4 of them for a larger screen. When doing your own testing, wait until it is dry before testing. I found different results between wet and dry. If the projector being too dim becomes an issue, thin the black paint with water before adding more aluminum ink. Also play with the order. All of my projectors including the dimmer ones worked with some variation of the test pictured. In all cases, I got better results than I did with a grey screen once I found a workable recipe.

I am going to post more pics when I get my next delivery of materials. These tests gave me some ideas! I think the 1.9 high index aluminum coated beads I have coming will make it possible to use a darker surface.
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post #62 of 516 Old 09-20-2013, 03:01 PM
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post #63 of 516 Old 09-21-2013, 01:40 PM
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Quote:
Originally Posted by New Design View Post

I am going to post more pics when I get my next delivery of materials. These tests gave me some ideas! I think the 1.9 high index aluminum coated beads I have coming will make it possible to use a darker surface.
Are you talking about the aluminum-coasted microspheres, or the half-coated microspheres? If the former, I'd be interested in what you think they might accomplish, if the latter, how you plan on using them and what size you've bought. Have you been able to find any ~ 10um microspheres at reasonable prices anywhere? The 2.8 HP apparently used 9um spheres (although not aluminum coated in any way). In the context of your other thread, the idea of half-coated microspheres in 3 different colors is intriguing, but absurdly expensive frown.gif

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
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post #64 of 516 Old 09-21-2013, 04:16 PM - Thread Starter
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Tests using window tint as the dark layer and mylar for the reflective layer:



Above, mylar with 1 layer of 50% tint. Not dark enough yet?



Above, with 2 layers of 50% tint. Now that looks a little more like it.



above, with the diffuser layer. It still looks black. Even blacker in person.



And with an image projected on it with the room lights on. Blacks look nice and black and the colors looks sharp and bright by comparison. Shows you don't need anything particularly expensive and hard to find to make it work well. Using multiple layers of lighter tint instead of one darker layer seems to work better. I'm not sure if more layers just blocks more ambient light or the gloss finish tint offer greter reflectivity under the diffuser. Perhaps they just let more light pass through to the reflective mylar layer. The other benefit is that for people with dimmer projectors who aren't sure how dark they can go, it gives the option of reducing the number of layers if there is a problem. I doubt that would be necessary for most.


The other point worth noting, if you already have a grey screen. Lets say it's this color:


You can add tint to your existing screen instead of starting again:


Then the diffuser:


And there you go, a black-screen finish for your existing screen so you don't have to start again.
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post #65 of 516 Old 09-21-2013, 05:57 PM - Thread Starter
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Quote:
Originally Posted by dougri View Post

Are you talking about the aluminum-coasted microspheres, or the half-coated microspheres? If the former, I'd be interested in what you think they might accomplish, if the latter, how you plan on using them and what size you've bought. Have you been able to find any ~ 10um microspheres at reasonable prices anywhere? The 2.8 HP apparently used 9um spheres (although not aluminum coated in any way). In the context of your other thread, the idea of half-coated microspheres in 3 different colors is intriguing, but absurdly expensive frown.gif

Check out this link. I haven't used anything from these guys yet so I don't have an opinion on how well anything works yet. They stock a lot of potentially interesting materials for the DIY enthusiast!
http://www.cospheric.com/P2453_solid_glass_spheres_retroreflective.htm

The beads I'm talking about here are an average of 50 microns and have a half shell alumnum coating. At that size, it wouldn't be visible without a microscope. It will just look like grey powder. At this point, I have don't a lot of testing with glass beads of various sizes. Every time it is discussed, the 9 micron bead screen is mentioned. Normally in the context of a reason why one can't make a DIY glass bead screen. As a general point, they aren't easy to find at that size bu they are available. I think the place for the link above stocks some.

I can tell you with a 100% certainty that getting them that small is not necessary. Once you get to mil spec 13# and smaller, the human eye can not see the beads individually. The concern with beads that are too large is a visible texture on the screen surface that makes the image look grainy and prevents you seeing high resolution detail. With 50 micron beads, even if you sit with your nose pressing against the screen, you still won't be able to see the texture.

There are a number of things that are important with beads but once you get smaller than your eye can see up close, size is not a major concern. I have successfully made a number of DIY glass bead screen with inexpensive beads from ebay. For $25, you can buy a 25lb bag of 1.5 index 25 micron beads. The texture is like fine powder. Having beads smaller than that didn't do the 9micron bead screen any good. The only review I could find for it, complained that it had a grainy image. Perhaps they screwed up the hard coat they set on top to make it washable.

In addition to the standard glass bead screen, there are a number of other uses for microspheres. One example is creating a high gain surface grey surface. Normally, using just a layer of aluminum paint or ink alone would result in hot spots. Mixing aluminum ink with glass beads will give you DIY aluminum coated beads. These can be set into a surface using a thin layer of glue or expoxy resin (as long as they are transparent. The resultant surface is a medium to dark grey screen which is smooth and doesn't hot spot. It will also retain some of it heir retro reflectve properties so you get a super colorful image when you watch on axis.

Creating a DIY half coat on the beads might be a little difficult without a microscope and a lot of time. I am interested to see how a half coating effects the reflectivity. However, the main reason I am I the rested in the beads in the link, is that they are high index 1.9 beads instead of the cheaper and more freely available 1.5 index beads. The proffesional reflective coating is just a bonus.

Now if you are looking for something that really makes a difference to performance, the refractive index is one of the main ones. Technically, the 1.9 index beads should be 7 times more reflective than the 1.5 index beads.

Forget about the 9 micron beads. All you need is beads that have a powder like texture - ie too small to make out individually without a microscope. Extra size decreases that you can't see won't help.

Also, without an aluminum coating, (DIY or otherwise) a glass bead screen will look white (like most commercial glass bead screens). Like any white screen, they will give poor performance in ambient light. The extra gain will not help and the image will still look washed out. The extra gain can even give more glare too. Aluminum coatings either on the bead, or the surface they are set in, result in a grey/silver screen which helps contrast. If you have a dimmer projector and plan on making a black screen or similar. Using the aluminum beads set into the reflective layer to give you a grey starting point, will mean you can get away with using less tint to give you that black appearance. Add a 50% tint to a white surface, it will look grey. Add 50% to a grey surface, it could come out black enough without sacrificing too much gain or viewing angle.

I plan on using the aluminum beads to set into a reflective layer like Mylar using a black epoxy resin. I'm trying to recreate the way DNP say they make one of their screens. They claim that half the beads touch the reflective layer, the rest protruded through a thin black layer and a small portion sticks out the front to pass light through the non-reflective black layer. The beads I'm using may be too small for me to achieve this but we'll see....

If you have an interest in a DIY glass bead screen, I'm happy to share my experiences. As a general point, they are very easy to make with cheap, easy to find materials using a variety of methods.

Search for sand blasting beads or sand blasting micro spheres on ebay and select mil spec 13# beads for a cheap source of suitable beads to experiment with. Any that describe themselves as powder will be fine (excuse the pun).

The place in the link is expensive and seem to be specialists. They even sell silver coated beads. I'd love to try those!
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post #66 of 516 Old 09-22-2013, 10:48 AM
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Black translucent paint over aluminium

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post #67 of 516 Old 09-24-2013, 06:22 PM - Thread Starter
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My micro louver film arrived from China and it turns out that it isn't micro louver film at all. It is just regular grey rear projection window film like the ones they sell on Ebay and claim (falsely) to be "sunlight readable". Who would have thought that the nice man in the Chinese factory would lie to me just to make a sale.....

I'm getting less bothered about micro louvers though. I made a test version using a number of smaller micro louver films attached to orca grow and covered with a diffuser film. It looked like this:


You can't see the borders when you project onto it but I would add another layer of tint to cover them if I was serious about this method, which I'm not right now.

Here is how it looked on. The bottom left corner is the micro louver screen:


This is it compared to my black-screen. I'm not sure I can see any benefit. Compared to white, with the lights on, obviously it will look better:


In the pic above, the bottom part of the Erased icon is micro louvered and the top is just orcagrow and diffuser.


The pic above is another test alongside my personal black screen. It kinda makes me question how much benefit those expensive micro louvers really offer. Perhaps the dark screen rejects ambient light on its own without needing them?

Or perhaps rejecting ambient light isn't really how they deliver a benefit. I think it is more likely that they just use pigment to make up for the projectors deficiency in producing blacks. This is easiest to see when projecting images that should be dark like the menu screen on my Sony Blu Ray player:




With the lights on, the white screen, even though it is highly reflective, is unable to offer even a hint of black.

With the lights off, orca grow is an amazingly bright screen surface on it's own. Better than most commercial white screens I have seen:


The bottom left corner is orcagrow against my black screen. If you only ever watch in darkness, this would be a great option.

If you watch in the dark but are particular about blacks, the black-screen offers another advantage which is less reflection on and off the white walls so for movies with black borders, you really can't see them:


Hard to see when the screen starts and ends. Check out the black background when loading a movie in netflix:


I'm not sure I'd be able to achieve that with a white screen. I'm also not sure that mirco louvers offer much advantage over just a black screen surface. I'll do more testing to see.
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post #68 of 516 Old 09-24-2013, 11:39 PM
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Hey those black screen shots look pretty good. Would you recommend micro louver film over window tint and what kind of diffuser do you use and where can i get it? I cant decide to really invest and experiment into this black screen material or just buy all 700 different things for the Silver Fire 2.5 7.0 confused.gif
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post #69 of 516 Old 09-26-2013, 09:21 AM - Thread Starter
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Quote:
Originally Posted by savesinner315 View Post

Hey those black screen shots look pretty good. Would you recommend micro louver film over window tint and what kind of diffuser do you use and where can i get it? I cant decide to really invest and experiment into this black screen material or just buy all 700 different things for the Silver Fire 2.5 7.0 confused.gif

The only micro-louver film I know of in the right size is too expensive for this in my opinion. I have a supplier for it but the cost to me is over $1200 for a piece big enough for my screen and based on the testing I have done, it isn't worth it. The extra benefit you might get has so far been invisible to me. Perhaps for certain room conditions it may make a larger difference but I couldn't find such conditions. In general, a black-screen using tint worked just a well.

All the materials you would need are available from tons of different sources. A quick google search will give you lots of possibilities and which one you go with will come down to taste and your lighting conditions.

I'll PM you some of the places I found but look for translucent rear projection screen material, matte finish frosted window film, rolls of light diffuser material and I'm sure there are others. I haven't tired it yet, but I have hopes for anti glare film with a matte finish.

Also, matte finish, anti glare plexiglass looks interesting.
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post #70 of 516 Old 09-26-2013, 09:58 AM - Thread Starter
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Quote:
Originally Posted by Greeting Ecards View Post


Black translucent paint over aluminium


Looks like you have found another option there. How did it look in person? Did you make the translucent paint by diluting regular black paint or did you find a brand of translucent black mix?

Were you using aluminum paint, ink or aluminum sheet?

I have a few of those Ricoh ultra short throw projectors. My black-screen doesn't work with ultra short throws because it uses a mylar reflective layer. Retro reflective surfaces direct light in a straight line. This would make the screen look great if I sat on the ceiling but not from in front of it. I use a regular projector for the black screen. LG use a light directing layer to deal with that problem on their black screen. Note that screen innovations does not recommend the black diamond for short throw projectors, they have a separate line for that.

For my ultra short throws, I have had much better results by using them for rear projection. I always think rear projection is superior to front for dealing with bright lighting. Normally, setting up a rear projection set up is a difficult, expensive and annoying process that requires a certain type of room with enough space behind the screen. Those mirror rigs are horrifically expensive too. Who wants to pay $10k for a mirror?? Now with ultra short throws, you don't need any of that. You just need about 1 foot of space which I can see from your clip that you have. The Ricoh ultra short throw has the best design out of any of them. It is 1/3 of the size of any other, 1/3 of the weight and has an internal mirror system which is upright. ie it projects up onto the wall instead of forwards making it far more compact. Check out this pic of my Ricoh's next to an equivalent model from NEC:

Above is my 2 Ricoh projectors on either side of my NEC ultra short throw unit. At less than 7lb, they are very portable.
These units will put out an 80 - 100 inch image from less than 1 foot from the wall which is amazing. In rear projection mode, they are more than bright enough to use in a bright living room with black rear projection material.

I will post a clip to show you how it looks but if I were you, I would go the rear projection route if you have your heart set on a black screen and don't want to buy a new projector. I have 2 for use in edge blending applications btw which that projector is particularly suited for.
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post #71 of 516 Old 09-29-2013, 10:48 AM
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post #72 of 516 Old 10-03-2013, 06:53 PM - Thread Starter
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There are some people who are just negative. You know who you are! You are probably already preparing a post with a 101 reasons why progress is not possible and why nothing could be better than your screen. There is no convincing you but for everyone else, here is the test that commercial screen sellers will never show you. It is also the one they should really show you and the one we would all want to see before parting with $5000 for a screen.

This clip shows a test with my black screen with direct light from my sun lamp. A sun lamp is meant to replicate direct sun light for people with seasonal affective disorder (or something). For this purpose, it is the closest I can get to replicating direct sunlight. It is ultra bright. Far brighter than anything you would ever have to deal with in a home theater or living room environment. It is many times brighter than normal room lights and it is directed like a flood light. When aimed directly at a screen from close range, it is brighter than most sunlight you would deal with. I am not suggesting that I have something more powerful than the sun, It is just harder to deal with at close range. Luckily for us, the sun is 93 million miles away.

I left some white screen material in the shot so you can see the impact of the sun lamp.

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

For comparison, here is a clip of a black widow screen under identical conditions. It offers a modest improvement over the high gain white surface but it still struggles.

http://www.youtube.com/watch?v=ue25C2SzP3Q

For context, here is a clip with the black widow screen without the sun lamp so you can see its performance against a white screen under modest ambient light. Without the direct light from the sun lamp, you can see a noticeable improvement over the white screen. It's nowhere near are good as the black screen but still better than just using white material.

http://www.youtube.com/watch?v=IEWJoh6DRsc

In fact, it's not that much different in performance to the $5000 Black Diamond Zero Edge 1.4 gain under far dimmer room lights in the Best Buy show room
http://www.youtube.com/watch?v=xqttD5wu9gg

For context again, here is another clip of the black screen under the same level of ambient light as the black widow screen without the direct light from the sun lamp. This is a typical level of living room light. The key difference is in black-level performance. The black widow screen does a nice job but it just isn't dark enough to allow the projector to produce solid blacks against the lighter material and room lights.

http://www.youtube.com/watch?v=BwfbErh3u4I


Now, the black screen with the sunlamp directly on it, is far from perfect but surprisingly, it is still watchable. Under this level of direct light, it is hard to make out any image at all on the white screen. On the black, there is signs of image wash out but it is still fully visible. I think it is important to show candid images including the limitations. It is wrong to pretend that any screen is completely unaffected by ultra bright direct light.

The difference between direct light and indirect light is huge. With smart light directing, I think a room could tolerate fairly high levels of indirect ambient light before the right screen starts to struggle. I think setting the goal of making a screen that can work well in high levels of indirect light is a realistic goal with credible options. I cant think of any reason why anyone would have to subject their screen to bright direct light in a real world setting.

The following pics really belongs on my other thread on selectively reflective screens but I got this shot with the sun lamp and the flash from my camera on the screen. I was testing a new type of transparent glue for sealing the layers of material and had some luck. It will take a few weeks for all the air bubbles to work their way out but none of the glue was visible which is the important point. The first shot captures the selective reflectivity under extreme amounts of direct light. I never get tired of seeing this one. When this idea is perfected, I am going to replace the reflective layer on my black screen with the selectively reflective one. I think this is a more credible way of "rejecting" ambient light than using micro louvers. Typical house lights are yellow which is not the easiest color to not reflect at all but it isn't impossible.





I think the selective method has the highest chance of delivering performance under direct light if it is ever going to be possible. Still it made me feel better when I saw that my plasma TV struggled against direct light from the sun lamp too
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post #73 of 516 Old 10-03-2013, 07:06 PM - Thread Starter
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While we're talking about cool things, check out my new Projectiondesign F32 1080 living room projector. I will post some pics when my lens arrives but I have high hopes for the combo of the F32 and my black screen.



I wanted one of these ever since I saw it at the Projectiondesign demo suite in Manhattan.
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post #74 of 516 Old 10-04-2013, 03:47 PM - Thread Starter
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Just like that terrible cooking show that my wife watches "semi home-made", I was thinking about how a DIYer can make screen designs with similar functionality to commercial screens. For example, what if you want a pull down manual screen that rolls up when you aren't using it or an electric screen that does the same. It occurred to me that it would be possible to buy one of the cheap commercial white screens and use it as a base to add more layers. It is possible to buy an entry level electric screen on ebay for very little money.

I did some testing with photo glue. This is a transparent spray glue that is designed to stick photos to surfaces without bleeding through the paper. I pulled out an old tripod white screen from the closet. A ghastly thing that is perfect for experimenting but not much else. I used the photo glue to stick a layer of mylar over the useless white screen surface:


The photo glue is relatively forgiving and allows you to make adjustments to get all the creases out. I didn't bother to spend the time doing that properly give this test, I just did enough to make sure that it is possible to get a flat surface.

I then used the same glue to add a layer of grey rear projection screen material to check that it is possible to attach screen layers without seeing the glue and without making it too thick to roll away. It worked fine as a grey high gain screen with the maylar reflective layer. I didn't make a black screen out of it. The grey material I used for testing isn't dark enough for that but there is no reason why this method wouldn't work in the same way for a black screen, or any other layered screen:



It worked fine and rolled away. It actually wasn't a bad method of making a grey screen that didn't suffer from having a low gain like many of the cheap commercial grey screens. The pics were taken with the 700 lumen projector and it still gave a watchable image with some lights on.

For scenarios where it has to be even thinner to roll up, and where low cost is not the primary goal, I did some testing with Mylar and self adhesive charcoal colored rear projection film. The films tend to be thinner than the PVC screen materials. The good ones also act as a light diffuser so you don't need to buy a separate one if the film has sufficient light transmission. I stuck the mylar to some foam board using the photo glue. I then stuck a piece of the charcoal rear projection film on top of the mylar using it's own adhesive layer.


The pic above shows how it looked. Not 100% black but far darker than any commercial grey screen and it is about as dark as most people would ever need it to be. Perhaps closer to a BD 1.4 than a 0.8 gain in appearance.
Performance wise, it does a nice job:




If cost is less important and you want an easy solution that can be added to your existing screen, this is a credible method that gives good results.
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post #75 of 516 Old 10-05-2013, 06:35 AM
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I just wanted to say thanks for all of your experimentation (and sharing all of your results with us)! Please continue! Once you have finalized the best non-painted screen for bright conditions, I will give 'er a go. While my .8 gain, grey screen is adequate, I would love to see better blacks during the day.
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post #76 of 516 Old 10-05-2013, 11:06 AM
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Yes, I'd like to second what joikd said. Although, don't know if it's just me, but with all the information you've posted it's difficult for me to tell what is what as far as your projects are concerned. I do tend to skim postings though, so maybe a complete project is in there somewhere. I will reread this thread. I guess maybe you're just in the "experimentation" stage. It looks as though you do have some really great possibilities and I would like to try one of your screen projects. If you have a complete project maybe you could start a new thread with the instructions for just one screen and its benefits as you see them.

I have a benq w7000 which I love, but it is lacking in the area of blacks and with a 16:9 screen would like to minimize the bars at top and bottom.

Anyway, I appreciate your efforts and hope you continue.
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post #77 of 516 Old 10-08-2013, 04:33 PM - Thread Starter
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With all the money I was able to save on my black screen, I treated myself to a new Projectiondesign F32 1080 with a wide angle zoom lens. Here is a clip of me using it in 1 lamo mode on eco in it's movie mode. The image is 115 inches. You can see a little where the image overshoots the screen because I am not using an anamorphic lens in this set-up but other than than, there is very little reflection onto the walls which adds to my viewing experience. I am glad I was able to achieve this without paining my walls black which would = divorce.

http://www.youtube.com/watch?v=d3WBjZPjDXw

Here is some pics too.





You can never fully tell from pics but it looks amazing in person. Much better than your average home theater projector.
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post #78 of 516 Old 10-09-2013, 06:41 PM
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Quote:
Although, don't know if it's just me, but with all the information you've posted it's difficult for me to tell what is what as far as your projects are concerned.

Yeah, seconded. It's kind of unclear what your screen actually is, what materials are used, or how it's made.
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post #79 of 516 Old 10-09-2013, 06:51 PM
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Yeah, I'm pretty sure he's never going to tell us specifically. He's been asked multiple times, but tends to ignore these requests.
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post #80 of 516 Old 10-09-2013, 07:05 PM
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This post is not directed at any specific member, but posted as a "warding off" of what seems to be a developing trend.

You bet....there is a lot to digest...and several different attempts and examples to examine, but the purpose and intent is clear enough if one actually reads "everything" as posted.

Sometimes in experimental DIY Screen making you can't win....give too little info and you stand accused of failing to prove the "why & how". Give too much...and nobody can seem to wade through it....or so they say.

This projects purports to do what no other DIY'er, singularly or as a group, has ever had the patience or the initiative to take beyond the most rudimentary stages. The few who have tried simply let the effort die. The Thread Starter is posting to both generate interest and document his efforts and progress.

Just as "discovering" a exlemeplary Paint solution require more than one singular attempt, this effort requires a huge amount of trial by error...and it seems it has achieved no small amount of success.

No one should expect a project such as this one to be "dumbed down" or condensed "Reader Digest-wise" simply to make it as easy to grasp as if you simply bought some sheets of Film and tossed them up on a wall. Read the info.....all of it....or simply wait for the final evaluation and material reveal.

Otherwise, as seen before in the past, demands and unreasonable expectations can often take the impetus out of the effort by someone who is giving up so much effort for the potential of others who will eventually follow. Post expressions of encouragement.....not critiques on how it's purpose and methods escape you.

Anyone can choose NOT to read the Thread....that is always an available option.

To quote James T. Kirk;
"I'm laughing at the superior intellect"

http://www.invisiblestereo.com
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post #81 of 516 Old 10-10-2013, 10:22 AM - Thread Starter
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Quote:
Originally Posted by Dennis Moore View Post

Yeah, I'm pretty sure he's never going to tell us specifically. He's been asked multiple times, but tends to ignore these requests.

I thought I have given an excruciating amount of detail on how I built my black screen and I documented each stage. Sometimes threads can become a victim of their own success as the more people post, the more there is for someone else to read through to find out what they want to know.

If I retyped it all, the same would be true again in a few weeks once more posts have been added on top. The only thing I haven't done in the public forum is name suppliers because I want to be respectful of forum rules and I don't want to be seen to be using this thread as a means to promote peoples businesses. Also, the materials needed for the screen are fairly generic easy to find. There is no requirement to use the same brands as me. Plus, I encourage people to test their own materials to make sure they work with their set-up.

There is no big secret, I promise. Anybody who has sent me a PM has received supplier suggestions.

At some point, I will post a link to a separate summary page so people don't have to read through a whole thread.

If you don't want to wait, you can start at the beginning of this thread and it's all there. To summarize, it documents the tests leading up to the completion of a diy black-screen. While I never stop testing and trying to improve my design, the project is materially complete. I have my diy black-screen on my living room wall and use it as my primary screen. I have posted pics and and video clips of it in use in both light and dark conditions and with multiple projectors ranging from 700 lumen portable devices to high brightness installation projectors.

It is a 4 layer screen:
1- a rigid layer to attach materials to (I use foam board but any flat surface or frame will work)
2- a reflective layer. I currently use Mylar on my main screen and Orcagrow on a portable test version
3 - dark layer - I use charcoal rear projection material but window tint works too. Any dark material that allows more than 20% - 25% light transmission will work - it is down to taste and your own projectors brightness which one you chose.
4- light diffuser film - there are tons of options for this. A google search for light diffuser material will reveal many options. You are looking for one that is as color transparent as possible and one that doesn't have a gloss finish. Translucent screen materials, frosted window films, rolls of light diffuser film can all be purchased for relatively little money. I found some as low as $40 for a piece large enough for a 110 inch screen. I found the more effective options were around $80. There are also anti-glare plexiglass options that I am sure would work for those who don't mind paying more and want a hard front surface. The only ones that didn't work were the ones that were too white (not transparent enough so you didn't end up with a dark finish), and the photography films from lee filter which were too glossy and gave hot spots - the light diffuser film is meant to prevent all hot spots

I attached all of the above materials to my foam board with staples. Just make sure they are all pulled very tight so you don't leave space between layers. I plan on using photo glue spray to attach the first 2 layers at some point.

The thread also shows a number of performance tests to confirm that the screen would work well in ambient light.

Here is a pic of my finished screen which looks charcoal black in person (somewhere in between a black diamond 1.4 and 0.8 gain in color). It is around 110 inches and I love it:

Here is another with something projected:


Hopefully this is clear. For anyone who is serious about making their own, I would take some time to read through the thread. It is only 3 pages with pictures so it won't take that long. It might save you making some of the mistakes that I tested for. It might also answer some of your questions and you will see the contributions of others. A few other members did some of their own testing on different methods and posted pics of results. My method is certainly not the only way of doing it. It is just the one that works for me, given that one of my aims was to use material instead of paint for all layers (to replicate the look of commercial screens). My painting skills are not good enough to deliver a super smooth finish like you get with materials (or 4K ready as the cool kids are calling it). for each layer there is lots of options and like I said, there is no need to use the same ones that I did. I have been helping people who have trouble finding them by PM.

Hope this helps.
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post #82 of 516 Old 10-10-2013, 10:45 AM - Thread Starter
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Ebay provides a rare opportunity to get a candid look at a black diamond zero edge 1.4 gain screen. Try as you might, it is very hard to find a pic of what the screen surface looks like on the internet without a projected image. Most of the imagery is their own marketing photos, even in the reviews. It is almost like they don't want you to know the truth, which is, that the black diamond 1.4 gain screen, which is the most popular model, isn't black at all. It is in fact grey and not too dissimilar to the Stuart Firehawk material although I was marginally more impressed with the Stuart screen.

Processed By eBay with ImageMagick, R1.1.1.||B2||T0JKX0lEPTVjYTFhYjFlYTY1YTAyYTIwNTIzYTNiNzJkMzhhZjA1MjRlMWI4ZTUxOGNkfHxPUklHSU5BTF9FQkFZX1FVQUxJVFlfU0NPUkU9NHx8Q1JFQVRJT05fREFURT0xMC8zLzEzIDc6MDcgUE0=

Processed By eBay with ImageMagick, R1.1.1.||B2||T0JKX0lEPTVjYTFhYjFlYTI1YTAyOGUwNTIzOWJiNDg2MzMyODA1MjRlMWM2YjA5OGQ5fHxPUklHSU5BTF9FQkFZX1FVQUxJVFlfU0NPUkU9NHx8Q1JFQVRJT05fREFURT0xMC8zLzEzIDc6MDcgUE0=

Now, here is the color chart on their website which is meant to tell you what the screen material looks like. According to them, the 1.4 gain material looks like this:


I just wanted to put the information out there so somebody ordering an expensive screen isn't surprised when it arrives. There is a danger that you just end up with a super expensive grey screen. My suggestion for anyone who intends to purchase one of the high end commercial screens, is to go with the darker option like the Black diamond 0.8 gain and the DNP High Performance material which is also 0.8 gain. I would go with the DNP screen myself (if I was in the market to buy instead of make). If anyone has one, I would love to see some candid pics posted and a view on how happy you are with it.

With modern projectors, many are bright enough to work with a 0.8 gain screen and benefit more from a boost in contrast to really let you take advantage of that brightness in a light room. Higher gain in a bright room doesn't help nearly as much as some people think.

As an FYI, the few that are being sold at a discount on ebay, have been damaged in transit. They have scratches in the hard coat. Does anyone have any insight into this problem? Is it easy to scratch the hard coat or is it a common problem. One ad claims the scratches happened because the packaging was too close to the screen in transit. That doesn't make it sound very robust.... I only ask because there is 3 on sale right now with the same issue. I think Screen Innovations should replace damaged screens like that, given the price they charge.

I guess an advantage with a diy screen is that replacing the front layer is relatively cheap and easy.
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post #83 of 516 Old 10-10-2013, 09:58 PM
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PM sent sir. Looking forward to a reply
Quote:
Originally Posted by New Design View Post

I thought I have given an excruciating amount of detail on how I built my black screen and I documented each stage. Sometimes threads can become a victim of their own success as the more people post, the more there is for someone else to read through to find out what they want to know.

If I retyped it all, the same would be true again in a few weeks once more posts have been added on top. The only thing I haven't done in the public forum is name suppliers because I want to be respectful of forum rules and I don't want to be seen to be using this thread as a means to promote peoples businesses. Also, the materials needed for the screen are fairly generic easy to find. There is no requirement to use the same brands as me. Plus, I encourage people to test their own materials to make sure they work with their set-up.

There is no big secret, I promise. Anybody who has sent me a PM has received supplier suggestions.

At some point, I will post a link to a separate summary page so people don't have to read through a whole thread.

If you don't want to wait, you can start at the beginning of this thread and it's all there. To summarize, it documents the tests leading up to the completion of a diy black-screen. While I never stop testing and trying to improve my design, the project is materially complete. I have my diy black-screen on my living room wall and use it as my primary screen. I have posted pics and and video clips of it in use in both light and dark conditions and with multiple projectors ranging from 700 lumen portable devices to high brightness installation projectors.

It is a 4 layer screen:
1- a rigid layer to attach materials to (I use foam board but any flat surface or frame will work)
2- a reflective layer. I currently use Mylar on my main screen and Orcagrow on a portable test version
3 - dark layer - I use charcoal rear projection material but window tint works too. Any dark material that allows more than 20% - 25% light transmission will work - it is down to taste and your own projectors brightness which one you chose.
4- light diffuser film - there are tons of options for this. A google search for light diffuser material will reveal many options. You are looking for one that is as color transparent as possible and one that doesn't have a gloss finish. Translucent screen materials, frosted window films, rolls of light diffuser film can all be purchased for relatively little money. I found some as low as $40 for a piece large enough for a 110 inch screen. I found the more effective options were around $80. There are also anti-glare plexiglass options that I am sure would work for those who don't mind paying more and want a hard front surface. The only ones that didn't work were the ones that were too white (not transparent enough so you didn't end up with a dark finish), and the photography films from lee filter which were too glossy and gave hot spots - the light diffuser film is meant to prevent all hot spots

I attached all of the above materials to my foam board with staples. Just make sure they are all pulled very tight so you don't leave space between layers. I plan on using photo glue spray to attach the first 2 layers at some point.

The thread also shows a number of performance tests to confirm that the screen would work well in ambient light.

Here is a pic of my finished screen which looks charcoal black in person (somewhere in between a black diamond 1.4 and 0.8 gain in color). It is around 110 inches and I love it:

Here is another with something projected:


Hopefully this is clear. For anyone who is serious about making their own, I would take some time to read through the thread. It is only 3 pages with pictures so it won't take that long. It might save you making some of the mistakes that I tested for. It might also answer some of your questions and you will see the contributions of others. A few other members did some of their own testing on different methods and posted pics of results. My method is certainly not the only way of doing it. It is just the one that works for me, given that one of my aims was to use material instead of paint for all layers (to replicate the look of commercial screens). My painting skills are not good enough to deliver a super smooth finish like you get with materials (or 4K ready as the cool kids are calling it). for each layer there is lots of options and like I said, there is no need to use the same ones that I did. I have been helping people who have trouble finding them by PM.

Hope this helps.
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post #84 of 516 Old 10-11-2013, 04:57 AM
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Forgive me; I didn't realize it was against the rules to provide suppliers. I'll PM any questions I have further. Keep up the good work.
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post #85 of 516 Old 10-11-2013, 08:55 AM
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Thanks for taking the time to test all of these various materials. From what I can see it looks like you have nearly replicated the Black Diamond screen material.

I have never seen a Black Diamond screen in person. I watched this video last night that shows the assembly of a Black Diamon screen. The back side of the screen appears to be similar to the mylar that you are using although it appears to have more of a matte finish... at least on the backside. You can see the screen unrolled at about the 1:15 minute mark:

https://www.youtube.com/watch?v=oeglr8UrjlY
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post #86 of 516 Old 10-12-2013, 05:56 AM
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http://revosoft.de/wordpress/hellraumleinwaende/

what is different than the other with this product?
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post #87 of 516 Old 10-12-2013, 04:01 PM
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Quote:
Originally Posted by Dennis Moore View Post

Forgive me; I didn't realize it was against the rules to provide suppliers. I'll PM any questions I have further. Keep up the good work.

As far as I know, it's not. Virtually every thread of this DIY sub-forum is full of supplier names, store names, product SKUs, and prices. I don't see any reason why the moderators would have a problem if ND decides to list materials and sources.
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post #88 of 516 Old 10-18-2013, 07:25 PM - Thread Starter
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I haven't been on here for a while but I wanted to post some pics of some tests I just finished for a new dark screen paint. I know I owe some pm responses to people too and I promise to reply to all of you shortly.

I promised to look into paint options a while ago and while I did come back with some info on painted black screens, I wouldn't say that there was a "finished" painted option out there yet. We know the basic principles but actually replicating the success of the fabric screen with paint, is a different matter. While working on the selectively reflective screen, by chance, I managed to create a working black-screen paint. As well as delivering a good image with decent brightness, the other parameters for the paint included: being paintable with a brush or roller without leaving streaks and that it can only be made with easily available ingredients at a price point that works for a diy project. Also, I wanted to create a paint that is opaque after a single coating.

One of things I hate about commercial screen paints is that they are typically very expensive and require multiple coats to stop light getting through. The main problem though, is that they aren't very good. From my testing of Screen Goo "digital grey", I couldn't detect any benefit over buying any neutral grey paint from an art shop for a fraction of the price. There is no legal definition of "screen paint" vs normal paint but it doesn't stop people trying to make the distinction. I have never felt so stupid as I did when I parted with $80 for a quart of grey paint. Great marketing on their part but it made me angry enough to start my own diy efforts.

Anyway, the problem with black screen paint is that normal black pigment used in paint, is specifically designed to reflect the least amount of light. That is why it appears black. In the fabric black screen, the dark layer is designed to allow a percentage of light to pass through unchanged. Black pigment is typically opaque on its own and after just one layer. This present a big problem. Normally, the make it reflective, you would add a lighter pigment, but, then you would end up with a grey screen. This leaves 3 options (that I can think of). One, is to add a translucent paint on top of the dark paint and hope you can make it thin enough and avoid streaks on the first attempt. Two, use translucent dark paint and apply it on top of a reflective layer. Find a reflective element that can be added to the paint without changing the color of the finish - the reflective element needs to be effective even after being submerged in black pigment.

After a lot of very frustrating trial and error, I came up with a mix that used elements of all 3 options to create a single paint. Allowing light to pass through paint in a way that lets you take advantage off multiple pigments in the same mix has been an issue previously. My starting point was transparent air-brush paints. These are designed to let light pass and allows you to see the color of the paint underneath. For example, applying transparent red onto black, would appear dark red.

I used a mix of transparent red, transparent green and transparent blue to create a dark murkey colored mix. To this, I added to transparent black until the mix looked black (ish). This dark mix on it's own would reflect very little. I found though, that adding treated aluminum powder to a dark paint mix will add reflective properties without significantly changing the color of the mix.

Taking a step back, I decided to use an acrylic tile adhesive as the base. This stuff is available from hardware stores for around $5 and is a white paste. You would normally use it to attach tiles to the wall. While the paste is thick, it picks up the color of whatever paint you mix it with. The paint thins the mix somewhat but you can add a little water too to get it to a point where it can be applied with a brush or foam spreader. I chose the tile adhesive because it is thick enough to cover any imperfections in the surface it is applied to and it can be sanded when dry which makes it extremely forgiving. No more having to redo the whole thing if you spot a small imperfection which can be sanded down in seconds. It allows you to create very smooth and professional looking surfaces with a $2 foam spreader and it doesn't leave streaks which can be annoying with other paints.

The other point about using a thick paste instead of a liquid paint base, is that the mix can carry other particles without everything sinking to the bottom. Anyway, now I have a charcoal black liquidey paste. To this, I added a small bag of the treated powdered aluminum and a handful of reflective glass beads (the latter is more for texture than reflectivity at this point). The treated powdered aluminum can be mixed with water to create a reflective paint on it's own. The trick is to add enough of this reflective powder that it can overcome with dull dark paint mix. As I said, the beauty of this stuff, is that it can do it without a major change in color . Adding white pigment would also increase reflectivity but not without turning the mix light grey. Adding aluminum powder means it will need some more water too, to keep the mix from becoming too thick. I found that adding gold and bronze metallic powders also makes a big difference to the overall brightness but that is one for the selectively reflective thread.

When enough aluminum powder is mixed in, the mix should appear charcoal black / dark grey. The color I was going for was slightly darker than the black diamond 1.4 gain screen (in color). The mix can be made brighter to make up for dull projectors but eventually, even the aluminum with start to lighten the mix. My paint looked like this:

Under the room light, the mix looks lighter than it does in person but you will get a better idea from seeing the color of the test sample.

For testing, I painted some foam board with the mix using a $2 foam spreader. For comparison, I also painted a patch of white screen goo. To make it a fair fight, I added a layer of aluminum ink under the screen goo. On it's own, the performance is too poor to make for a decent test. I didn't add a reflective layer under the charcoal paint although I plan to experiment with a thinner mix and additional layers at some point. For now, I'm keeping it simple - a dark screen surface which works as a single layer. Here is a pic of a test sample:


Above is how it looked under the light. Here is how it looked without light shinning on it:


Next came testing. This is where I ran into some issues that made me rethink the testing process. Here's the problem, our eyes are drawn to and adjusted by the brightest point on the screen. I like a side by side comparison as much as the next guy but, for lower gain screens, an image can look dull when compared to white, but, look great as soon as you take the white sample away. essentially, the higher gain white surface, while still washed out in a bright room, makes the colors on a lower gain screen look less vibrant. The human eye however, is very efficient at adjusting to less brightness but it doesn't do so well with poorer contrast. Even though I would love to compare the black paint to a white surface, you get a better impression of how the mix performs when you see the pics separately. I'll show both so you can see what I mean.

I'm going to move into a new post so I don't lose what I just wrote
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post #89 of 516 Old 10-18-2013, 09:00 PM - Thread Starter
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OK, pics of results. Before I post some, it is worth mentioning that this mix is not jet black and is not intended to be. It is far darker than any commercial grey mix available though and much darker than diy mixes like black widow. I will also say that in performance, it is not as good as the fabric black screen but it is cheaper to make and if you are not comparing it to the fabric option in a side by side, it gives very pleasing results. I would estimate the gain to be around 1 which is fine for most modern projectors. The gain can be increased by making it slightly lighter or, making it thinner and adding a layer of aluminum ink below it.



In the pic above, the black paint mix is at the top of the foam board and you can see some of the white paint / aluminum mix at the bottom. I should also state that this test is more "real world" than other tests I have done. The lights are on but the room is not massively bright. There is little sunlight and most of the brightness is from the room lights. This would be typically living room brightness that is representative of how I would watch. I am not going out of my way to shine direct sunlight on the samples. I am using my Projectiondesign F32 1080 set to single lamp mode in eco setting. It is also set to movie mode so I am probably putting out 1500 - 2000 lumens. I tested the mix with a 700 lumen device too and it worked fine. Testing with this projector has been harder than normal because it is so good, it puts out a great image on most screens. It's like testing how much faster I get around a track with an engine mod in a Ferrari - it is easier to see the improvement caused by a screen if you don't start with an amazing image. I can still see differences, it just makes it harder to capture the improvement in photos.... For the test, I found the best images came from shots that didn't have screens with multiple different levels of brightness.

For example, the following pic shows the netflix red logo on my fabric black screen (top) and the painted black screen (bottom). The paint option looks dull in comparison and if I stopped the test there, I would have drawn the wrong conclusion.


Here is a pick of the netflix red logo close up, only showing the black painted surface. Without a brighter comparison screen, the colors look vibrant with good contrast and pure whites:


Here is another pic to illustrate the testing problem. It shows the white test patch with the fabric black screen behind it. For the fabric screen, the shot is off-axis (the black screen is brightest from in front of it like all retro-reflective surfaces). The image makes it look like the white paint is bright with vibrant colors while the black screen is dull.
This really isn't the case btw.


Here is a pic from a more central point:


The pic above is a little more representative of what I saw in person but still misleading. Here is a similar shot showing all 3 surfaces:

In the pic above, the black paint is on the right, the white paint is on the left and the fabric black screen is in the background. The black paint, again, looks dull in comparison to the other 2 as it has a lower gain. If I take a shot only showing the black paint surface though, our eyes adjust and it looks good:


To further complicate things, the part of the screen occupied by the black painted surface, is darker than the area above it. As expected, scenes with light colors are enhanced by the white screen while scenes with dark areas are unwatchable with the lights on. The main problem with the comparison though, is the tricks our eyes play on us when there is a brighter surface to compare it to. This speaks to flaws in side by side comparisons generally, it was just less noticable with the fabric black screen which has both a decent gain and high level of contrast. The next pics I am going to show, only have the black painted surface because, it looks really good on it's own. While not as good as the fabric option, it is far better overall than the white paint. With lights on, there is no comparison. The gap would be even larger if I was using a lesser projector. The F32 is bright enough to put out a good image with the lights on, even with a white screen. If you have a less powerful device, the black screens improved performance will be far more noticeable as no white screen looks good with the lights on with home theater projectors.


Look at the Louis CK icon in the pic above. The colors look good. If I try and take a photo including the brighter fabric screen behind it, my eyes start to play tricks again and the same image, with the same projector, taken using the same camera, now looks dark:


The key point is, the paint works well, it is just hard to take comparative photos to show you what I'm seeing. There is also the point about calibrating the image to the screen. adjusting the projector brightness a few points can eliminate any difference in perceived brightness.


Above, Spy kids icon with half black, half white. Below, Just using the black paint surface:


Scenes with black backgrounds have the reverse issue:


With black backgrounds, the black painted screen looks far better than a white screen with the lights on. This is predictable but the difference isn't as great as the pic suggests. While the white screen does look washed out without blacks when the lights are on, the side by side comparison makes the white surface look worse. On it's own, the difference is 50% less although still obvious.


Above, the black border on a 2.40:1 movie. The black painted surface outperforms the white surface as predicted.



The pic above shows a black image with the lights off. Half is on the white paint, the other is on the black paint. Even with no room lights, the black paint delivers noticeably better blacks that the white surface. The difference is more noticeable in person and the improvement does not just apply to a room with ambient light. White is known to be a more forgiving color but I found better color accuracy with the black surface too. It may be my fault for adding an additional reflective layer to the white paint but I saw more color shift from that surface


The pic below is a white paint / black paint comparison taken with the flash on my camera on.

The lower gain black paint mix with enhanced RGB reflectivity is far less affected by the bright light of the flash.

The headlines for all this are:
- I'm close to having a workable black screen paint mix
- Please don't experiment with untreated powdered aluminum at home - it can be very dangerous. Only uses treated bright aluminum powder
- all the ingredients I used are easily available
- Preliminary tests with gold and bronze metallic powders to enhance color vibrancy are really promising. More to come!

I plan to upload a video clip of a test for the black paint shortly which I think will do a better job of demonstrating it's potential. I am going to abandon side by sides with white screens for now (until I find a way to get it to a comparable gain). I will post separate pics of white screen tests for comparison though. To date, this is the only single layer black paint mix that I have seen that works. Does anyone know of any others?
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post #90 of 516 Old 10-18-2013, 09:59 PM - Thread Starter
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Now everybody knows that children are a punishment for one night of fun with the wife, but children's movies are great for showing off projectors and new screens. Here is a clip of the black-screen paint mix in action.

You can see right away that, without direct light shinning on it, it looks a lot darker than it did in the photos. The clip has some close-ups of the screen surface in action as well as some shots further back so you can see my fabric black screen. Think slightly darker than a black diamond 1.4 gain screen surface in color. I am just finishing a sample of the same with glass beads added on top. I'll post some clips showing that test soon. For now, here is the first clip of the black screen paint mix in action:

http://www.youtube.com/watch?v=SHj-gXOpDrc

I like it! Soooooooooooo much better than Screen Goo!
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