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post #91 of 404 Old 10-18-2013, 10:06 PM
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wow. i'm thoroughly confused.
don't mind me saying this but... talk about reinventing a round wheel with crudely square pegs...
forgive me for being blunt here... or perhaps you haven't done much reading into what silver fire is. nor have you ever seen a sample of silver fire as a very viable rear-projection screen.
there's not a single revelation here that isn't already built into and already well thought when it comes to silver fire.
look, i don't want to dampen your DIY spirit of enthusiasum but...
from your explainations of black to this particular mix... it's really very crude... and my opinion is... it needs to be a little better
thought out... and have a more unique identify of it's own. because right now, it's just rehash of silver fire using b-quality components.

as for the comparison of a black screen mix or screen to a white screen...
"i no longer find it to be an apples to oranges comparison ESPECIALLY in controlled lighting, and ESPECIALLY in on-axis viewing"
in fact, such side by side comparisons are the ONLY way to find out if your black screen is worth it's weight.

a black screen in controlled lighting should show little to no difference in white levels, skin tones, or color shifting... with the exception dark colors having slightly more richness... however, the hue of the color should not shift.

consider the following screenshots...

here is side by side comparison of a diy black screen to a white sintra screen. (with no image. the pencil you see sits on top of the 2 side by side screen samples)


and here are 2 screen shots of the two screens side by side...
notice... that little to no color shift exits between the two screens... regardless when it's something as tricky to get correct as skin tones...
nor in medium to dark colors as well...as there shouldn't be any readily noticeable shifting of colors or changes in hue either.
truth is, if it's worth any salt.. in controlled lighting... the two screens should be nearly identical.



don't get me wrong...i don't question the effort being put forth.
but i'm also looking closely at the results. and for now, much needs to be done before it's not 'just another grey screen'.
and believe me, that not just me talking... ...rather it's me taking the brunt of the heat thrown at me... and still willing to take the long and winding road instead of the much traveled (accepted white) one.
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post #92 of 404 Old 10-19-2013, 07:20 AM
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PB...don't be too hard on him.

He is trying to go about doing things his own way through his own ideas and thought process. And it's be a long while since anyone bothered to contribute so much effort to any application, let alone to the one being considered. I'm certain the goal is to create something new...and hopefully something exceptional.

The complexity, cost, and end results will bear final witness, and determine the degree of acceptance any such application receives. I do agree, the posted results do lack any real emphasis on Image Quality, but that might be explained by New Design's own inability to take good representative photos. We both know that can be a duanting prospect.


Heat? Whose tossin' Fire Bombs at one of the most valued contributors on this Forum? I won't have it! mad.gif

That's "My" position!

(...leastwise the Fire Bomb part. biggrin.gif )

To quote James T. Kirk;
"I'm laughing at the superior intellect"
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post #93 of 404 Old 10-19-2013, 02:00 PM - Thread Starter
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Quote:
Originally Posted by pb_maxxx View Post

wow. i'm thoroughly confused.
don't mind me saying this but... talk about reinventing a round wheel with crudely square pegs...
forgive me for being blunt here... or perhaps you haven't done much reading into what silver fire is. nor have you ever seen a sample of silver fire as a very viable rear-projection screen.
there's not a single revelation here that isn't already built into and already well thought when it comes to silver fire.
look, i don't want to dampen your DIY spirit of enthusiasum but...


Reinventing the wheel? Direct me to anywhere else that describes how to make a diy black-screen. I did a lot of searching before I started the project and found nothing but I'll be happy to read anything you can direct me to. I'm not sure what you find so confusing but I'm sure you can figure it out if you try! It is very simple. What is your stake in Silver Fire that makes you angrily defend it like that (even though I wasn't criticizing it)?

I am not questioning the quality of the Silver Fire design. Mississippi man is a fan of it and I respect his opinion a lot. We have spoken on the phone and shared ideas. It is just irrelevant to this thread. This thread is about building a diy black-screen only. Not in any way a criticism or advertisement for other diy methods.

I have a number of screens and I like them all in there own way. The beauty of diy is that you can keep changing your screen until you find one you like. There are tons of threads on Silver Fire where I'm sure you'll find other people who like talking about it as much as you. I did read about them and even learned something from them before working on my own design. Keeping an open mind is good like that. Mississippi man said he had gained some new ideas from the black-screen work too.

While I think the fabric diy black screen is the best DIY option available, I accept that it is not the only good screen design out there. There is room for more than one. That allows people to build the one they like best. The problem with posting stuff on this thread about other screens is that it takes up space making it harder for people to find info on what they came here looking for. I guarantee that isn't another opinion from someone who is angry about s description of a diy method that isn't the one they use.

The black screen concept is an area of interest to a lot of people. In diy terms, it is one of the most important because it is one of the few areas where it is possible to make a big saving (given the cost of commercial offerings). White, grey and silver commercial screens can all be purchased for very little money these days.

On image quality, obviously that is the most important but it can't be captured with a camera. Even the best cameras don't do it justice. Things that you can see with pics do include ambient light performance which is the main point of the black screen. In my opinion, reflectivity, build quality and surface texture make the most difference to image quality (other than the projector of course). The advantage of the fabric DIY black screen (or hybrid paint/diffuser) is that you get a level of smoothness that is impossible with paint and a roller. To date, I haven't seen any painted screen with a better projection surface and I have tested far more than most people. If you post pics to show image quality, separating which part comes from the quality of your projector, vs the screen, vs the room conditions vs the camera quality vs the contents suitability for the projectors specification is impossible and not that useful.

Rambling about how everything has been done before is one of the biggest barriers to progress. Somebody reads something once and it becomes written in stone without anyone understanding why, or questioning it. New projectors come out all the time. New projection technology is being introduced and they are getting brighter. New materials become available but, you think every combination of every material has already been tried? Modern projectors with increased brightness have opened up new options for screens. Regardless of that, you can't possibly think that current screen options represent the pinnacle of what is possible? It isn't exactly an area that has had the worlds best and brightest working on it. Maybe I have higher standards than you do, but, I started the black-screen project because none of the other diy methods came close to the level of performance I wanted in my living room. My options were to part with $5000 for a commercial screen or do a little research of my own.

Progress is good for everyone. I think we have only just started seeing the age of the engineered screen. Projection has many advantages of TVs if a few basic problems can be solved.

Not being able to use the projector in a room with lights on has been a weakness for technology since the beginning. We all know that digital display devices can't produce black so they need darkness, or a black projection surface to beat room lights. Grey screens are a compromise but they don't fully solve the problem. With the black screen, I get great blacks, even with the lights on. No other screen type allows this to the same extent (that is true without exception). That is why the hype on black screens excites people. Even if you have a dedicated dark room, it is nice to have the option of not watching TV in total darkness.

Now, I would like to see you take your knowledge on Silver Fire and find a way of incorporating the best aspects into a black screen design (if you think it is lacking in an area). If you post info on that, I would be very interested and it would be a real contribution to the thread. Be a contributor. Don't be angry about new ideas. Take what you like and ignore the rest. I wish everyone would do some testing and post results from new materials.

As a matter of interest, can you tell me why you clicked on a thread labelled DIY Black-screen tests, if you believe you have seen everything before and are currently using a screen that can't be bettered? It seems like a poor use of time....
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post #94 of 404 Old 10-19-2013, 02:08 PM
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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.
eek.gif Dude! I think it's great you posting all of your efforts, but you are literally playing with fire!!! Please, please do some research before you mess around with aluminum powder again! Danger Will Robinson! Danger!
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post #95 of 404 Old 10-19-2013, 04:04 PM - Thread Starter
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eek.gif Dude! I think it's great you posting all of your efforts, but you are literally playing with fire!!! Please, please do some research before you mess around with aluminum powder again! Danger Will Robinson! Danger!


Dude, I said "treated aluminum powder" and specifically said not to experiment with untreated aluminum powder as it's dangerous. Treated powder is brighter as the treatment stops it reacting with the air around it. Untreated, aluminum reacts with oxygen. As well as making it volatile, it also causes an aluminum oxide crust to form on the surface which reduces brightness. Treated aluminum is safe. You drink soft drinks out of it.
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post #96 of 404 Old 10-19-2013, 04:45 PM - Thread Starter
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Now, here is the paint test that I was asked about specifically. The idea is a hybrid approach which uses a painted dark layer but a diffuser film for the front surface. I posted some small tests like this a while ago but only small squares. Todays test involved creating a 70 inch test board to place in the center of a 110 inch image. The test is under living room lighting which for me, includes a center light with 3 100 watt bulbs and a side light with another 100W bulb. This is how I would watch in real world terms during an evening.

I took the charcoal black paint mix and applied a thin layer on the back of a single sided transparent diffuser film. The film isn't 100% transparent but close enough not to alter the appearance too much.Before the paint mix was dry, I applied a layer of 25 micron glass beads. The coated diffuser was attached to a piece of foam board with a layer of orcagrow (although I don't expect it to have much impact with paint as thick as this). I placed the board next to my regular screen. Here is a pic of the test setup:



Here is a closeup of the test surface:


In person, it looks slightly lighter than the paint on it's own but not in a significant way. The appearance would still be described as charcoal in color. I have thinner diffuser films if I wanted a darker look still, but I chose not to use them for an experiment. The finish is darker than a black diamond 1.4 gain screen which was what I was going for in this test.

It worked really well. The smooth finish from the diffuser took away the crude look of the paint to make it look more professional and it added some additional brightness which looked uniform too.

Here are some pics with the surface in use. I left a border unpainted so you can see where it starts and stops:


Here is a closer look


I have a lot of flexibility in my motorized lens shift so I moved the image down to cover more of the test screen. That also allowed for a look of it next to the image on the white screen underneath.


For images with a black background, it retained the dark images even with the lights on which is the main point:


With the smooth, high quality diffuser, the image looked crisp and sharp:


Similarly, the black borders on 2.40:1 content remained suitably dark:


I still prefer the all fabric option but I thought this approach worked really well. If I thinned the mix and added a retro-reflective layer under the paint, I think that would add some additional pop - assuming I can do it without losing the dark layer or making it look to grey. I have some transparent white air-brush mix on the way. I am going to try applying it with my air brush to see if it is possible to replicate the fabric diffuser. I realize that most people don't own an air-brush but they can be picked up for $40 plus $10 for propellent if it gives good results. Of course,diffuser film can be picked up for not much more than that so perhaps it isn't worth it.

The hybrid approach has the advantage of being easier to seal all the layers. A layer of Mylar could be glued to the painted surface and with the paint applied directly onto the diffuser film, that would give a single piece of screen material that can be rolled or stuck on top of an existing electric screen.

Adding the glass beads to the mix gave it a useful lift in brightness. For people with some of the lower powered projectors, it could be the difference between it being bright enough for living room use or not. It worked without them but they defiantly added some pop. I am also sure that this approach would work with other paint mixes and add something in the process too.

If you look back to the beginning of this thread where the initial tests used an all paint design, the diffuser layer used translucent white paint. The problem was that it was unforgiving to mistakes and not smooth enough for my taste. Using paint and a diffuser fixed a lot of my concerns and is definitely a viable option that could look very professional if done well. Just don't screw up the paint job so you have to throw away the diffuser film... It is defiantly the least expensive option.

I hope that answers the questions about a painted option.
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post #97 of 404 Old 10-19-2013, 06:23 PM
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Dude, I said "treated aluminum powder" and specifically said not to experiment with untreated aluminum powder as it's dangerous. Treated powder is brighter as the treatment stops it reacting with the air around it. Untreated, aluminum reacts with oxygen. As well as making it volatile, it also causes an aluminum oxide crust to form on the surface which reduces brightness. Treated aluminum is safe. You drink soft drinks out of it.

Your warning about untreated powder was in a later post that I did not read. Assuming that the "treated" aluminum powder you are using is treated specifically for use around moisture it usually is considered "generally safe" as far as a fire hazard is concerned. It is NOT considered safe as far as health risks go. The concentrations you are dealing with are far different than what is found in soft drinks. If you think it to be as "safe" as soda pop, my guess is you aren't taking adequate precautions to safeguard your health. That's fine, it's your health. Don't promote it as "safe" for others to use without adequate safety measures though. (Ventilation, rubber gloves, full face respirator at a minimum.)
Quote:
Potential Health Effects
Eye: May cause eye irritation.
Skin: May cause skin irritation. Low hazard for usual industrial handling. No sensitizing effects known.
Ingestion: May cause gastrointestinal irritation with nausea, vomiting and diarrhea.
Inhalation: May cause respiratory tract irritation. May cause respiratory difficulty and coughing.
Chronic: Aluminum may be implicated in Alzheimer's disease. Inhalation of aluminum containing dusts may cause pulmonary disease.
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post #98 of 404 Old 10-19-2013, 08:31 PM
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look, i wasn't being hyper-critical of your effort... far from it. in fact, i have encouraged it.
but, there seems to be a lot missing or desired from this current effort.

even when i joined avs and started as enthusiastically as you...
i still had the respect to pay homage to those who went before me.

it's apparent you have no idea that Silver Fire is exactly that... a Black Screen concept from top to bottom.
to say that no such solution exists is a complete lack for disrespect for Silver Fire as a BlackScreen...
especially when EVERY aspect of your latest effort is an EXACT mimick of every conceptual point of Silver FIre...
using from what i can see... in some cases, 2nd rate mediums for every aspect of what Silver FIre already is.
it also tells me that you really haven't done your homework with respect to the DIY mixes before you... and especially Silver Fire.
and that you choose to ignore or don't bother to know the CAVEATS that make many cringe at the thought of any screen, whether grey, black, or otherwise.

now if it were me... i would have said this...
"...i have an awareness of many of the logical steps of another blackscreen... ie silver fire... and borrowing some of it's concepts... while adding or altering this, that, or the other... because i feel it can be improved here, there, and there... etc..."
then i may have approach my critiques in a different manner.

however, at the end of the day... if your results don't begin to wash away and eleviate some/or many of the concerns of the caveats of grey and black screens and how they hold up against white screens for critical viewing... then my critique and theirs will remain the same... and lest your blackscreen efforts be deemed as 'just another grey screen' as i see many positives in not only the effort (which i have stated before) but also in some of materials/mediums brought forth.

----

now with respect to your diffuser ideas.. mm and i have talked about how interesting that is and how we can work with you to blend some concepts. we did some things very similiar in the past without much success... in which we sprayed RS-MaxxMudd screens with a couple coats of straight polyurethane. the lack of Matte polyurethane at time resulted in a screen with too much sheen.
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post #99 of 404 Old 10-19-2013, 11:09 PM
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here is side by side comparison of a diy black screen to a white sintra screen. (with no image. the pencil you see sits on top of the 2 side by side screen samples)


and here are 2 screen shots of the two screens side by side...
notice... that little to no color shift exits between the two screens... regardless when it's something as tricky to get correct as skin tones...
nor in medium to dark colors as well...as there shouldn't be any readily noticeable shifting of colors or changes in hue either.
truth is, if it's worth any salt.. in controlled lighting... the two screens should be nearly identical.


Very impressive. In those screenshots, are the two screen samples physically side by side, or are the photos taken separately and combined into a single split-screen effect one? Do you have similar comparisons using something easier to judge like a black/white checkerboard?

I would love to get one of those samples of the DIY black screen in your photos. I will paypal you for shipping costs and your time.
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post #100 of 404 Old 10-20-2013, 05:38 AM
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Ha... I think that's probably just a dark Silver Fire? I could be wrong.
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post #101 of 404 Old 10-20-2013, 07:04 AM
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yes, those 2 screens are physically side by side in the same screen shot.
----
my apologies guys... as i do not want to side track this thread any longer and listen/read/view ideas being brought forth.
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post #102 of 404 Old 10-20-2013, 08:35 AM
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this latest effort... with respect to a hybrid... is something that MM and i have recently discussed.

back in 200?. i paid MM a visit to work on a restaurant opeing where we installed several large screen including a rear projection screen in the front window to be seen from the street... that was flooded at night with huge security lights.

we decided to use a P90 substrate. the P90 is a 1/4" acrylic with a manufactured difuser layer on one side.
we ended up scrapping the idea for critical viewing due to the granularity of the difuser layer coupled with how the duster droplets of the 1st couple of layers dried when sprayed on the difuser layer. secondly when sprayed on the acrylic side, the 1/4" acrylic between the difuser layer and the layer itself created a defocusing of the image.

we did however, make note how much we loved the image as a non-rear projection... ie front projection. however, since it was not a leaps and bounds kind of better... and because of the COST of a single sheet of 4 x 8 was cost prohibitive to DIY... we never persuded the alternatives.
i also verified a concept i believe to be a very real possibility but have never introduced my ideas to this forum.

long story short... mm and i have already seen for ourselves the possibility this hybrid effort.
especially now that more cost effective materials are available.
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post #103 of 404 Old 10-20-2013, 12:05 PM - Thread Starter
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Quote:
Originally Posted by pb_maxxx View Post

this latest effort... with respect to a hybrid... is something that MM and i have recently discussed.

back in 200?. i paid MM a visit to work on a restaurant opeing where we installed several large screen including a rear projection screen in the front window to be seen from the street... that was flooded at night with huge security lights.

we decided to use a P90 substrate. the P90 is a 1/4" acrylic with a manufactured difuser layer on one side.
we ended up scrapping the idea for critical viewing due to the granularity of the difuser layer coupled with how the duster droplets of the 1st couple of layers dried when sprayed on the difuser layer. secondly when sprayed on the acrylic side, the 1/4" acrylic between the difuser layer and the layer itself created a defocusing of the image.

we did however, make note how much we loved the image as a non-rear projection... ie front projection. however, since it was not a leaps and bounds kind of better... and because of the COST of a single sheet of 4 x 8 was cost prohibitive to DIY... we never persuded the alternatives.
i also verified a concept i believe to be a very real possibility but have never introduced my ideas to this forum.

long story short... mm and i have already seen for ourselves the possibility this hybrid effort.
especially now that more cost effective materials are available.


The funny thing about light diffuser films is that they are available under different names and for different purposes as prices ranging from $40 to $2400 per roll. The difference between the highest and lowest isn't quality, it is the function they are selling it for. When any film is sold specifically for projection, the prices seem to grow arms and legs. I have seen different price points for the same material from the same supplier (depending on which icon you click on). Projection users have been ripped off for too long. We are seen as this niche obscure market and a soft target. Almost like we are idiots who will pay $5000 for a piece of material.

Most of the decent viable diffuser films I found cost around $80 for a roll long enough to make multiple (large) screens. The materials I tested that cost $400 - $600 were no better and in many cases, were worse for our purposes. Self adhesive ones seem to attract ridiculous premiums. Who knew glue was so expensive. Photography diffusers are far less expensive but not all diffusers, will diffuse light properly which is where it gets confusing and testing is needed. More confusing still, is that most of the options are not even marketed as diffusers specifically. They just happen to be diffusers under a different name which can make searching more time consuming that it should be.

The other point about the availability of lower cost materials, is that options for the dark layer and the reflective layer are also freely available at DIY friendly prices. In most cases they outperform painted alternatives (for black screens) due to the precise and stated light transmission. Black pigment is very tough on light transmission and reflectivity for obvious reasons and using layers of non-translucent paint is less effective. Tinted films, that are designed to allow a percentage of light to be transmitted unchanged, are an easy option and far more forgiving. One mistake on the painted layer, and you have to throw away your $80 diffuser. Not a big deal for professionals but many DIYers only ever make one or two screens in their life and the chances of mistakes are higher. Also, materials like mylar and orcagrow outperform any reflective paint I have seen. For some reason, genuinely highly reflective paints seem to be beyond the skill of paint makers. Even the reflective paint sprays offer mediocre performance. The mylar, tint, diffuser combo retains great contrast and gain (as long as you sit in front of the screen). For commercial users, the issue with paint is how well it travels after it is rolled up and shipped. It occurred to me that the acrylic paste I used for a base would crack when dry if I bent the film. On a wall, it is great - especially because it can be sanded smooth if needed.

I looked at painted options because I promised a few members that I would, but ,I would probably encourage most people to spend the extra $60 - $80 and go all fabric if they are building a black-screen. It still comes out far cheaper than the commercial offerings by a factor of 10x (minimum) and 20x+ in some cases. It is the right approach for all but the most extreme cost conscious DIYer. If you are spending $120 on materials, spending $180 instead is probably worth it to get a finish that looks professional and that you'll be happy with. I would say though, that painting the back of the diffuser film does close some of that gap when it comes to commercial quality finishes.

I think you should get some diffuser film and try it with your favorite paint mix to see if you like the way it looks. The key things to look for are transparency and a matte finish. I have seen a number of materials that are all white and glossy but claim to be diffusers. Transparency is key or you will lose the look of the layer underneath.
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post #104 of 404 Old 10-20-2013, 03:07 PM - Thread Starter
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I took advantage of the last of the really bright sunny days in New York for this year and got some shots of the black-screen in action with an eye on further opportunities to improve the design.

I never get tired of seeing this smile.gif

Here is a pic of my screen with the lights on and the blinds open during the afternoon with bright sun. My living room is a projectors nightmare with white walls, white carpets, white ceiling and a large window right next to the screen. Room lights are one thing but with sunlight pouring in, that is a different challenge:



While comparisons to other screens are fun, the performance in challenging conditions is what counts here. Here is the same pic with the blinds closed and lights off. With white walls etc and marginally effective blinds, the room never gets very dark during the afternoon. This is the darkest I could make it though:


The screen is set to 110 inches. With my lens, I can zoom it all the way to 170 inches without moving the device. Under my black screen, is a 150 inch white screen which I used to use before I built the black one. I zoomed the image until it came off the edge onto the white surface for a side by side:


Now, it's no news that the white surface is inferior with sunlight pouring in. The extent to which it is washed out though, shows the level of brightness it is contending with. For the shot, I adjusted the settings to try to optimize them for the white surface but it didn't make much difference. You can barely even see that an image is projected on the white screen. Here is a slightly closer look:


Here is the same shot with the lights off. Note how the reflection off the white walls makes the room brighter You can see why nerds paint their walls black:


I criticize reviewers who compare a black diamond or Supernova to their reference white 1.0 gain screen and state the revelation that the black screen is better with the lights on. A grey screen would be better than the white screen too while we are stating the obvious. In this test, I was looking for opportunities to improve the design.The comparison to white is only to give some idea of the conditions that the screen is dealing with. It is hard to tell room brightness in a pic . With bright room lights, my projector will give a good image, even on white. It is only against sunlight that this level of wash-out occurs.

As much as I love my screen, I identified a few areas with opportunities for improvement. The primary one is surface glare. I noticed a fair amount of glare on the black diamond screen at best buy and that was without any sunlight. Mine has less glare (in my opinion) but, in really bright conditions, I can still see some glare off the translucent layer. It is reasonable to assume that increasing ambient light will increase glare until you reach a point where the image is no longer watchable and that this should be true with any screen.

On my setup, It isn't easy to see the impact of glare until it gets brighter than I would ever have it in a real world setting but still.... It is the difference between the crisp sharp image that is full of Pop that I get with room lights on and the watchable but not optimal image I get under super high levels of light. Its nothing I can't live with but while I'm in DIY mode, why not explore all opportunities to enhance it.

I decided that I want to test a 5th layer which would be an anti-glare / anti reflective transparent surface and possibly even a scratch resistant finish.. This is different to the diffuser layer. The diffuser film takes care of hot spots from the projector but not all of the glare from the sunlight. . I think it would make watching in super bright conditions comparable to watching with just room lights in an evening (we'll see). I also think that it will increase the viewing angle (in high ambient light). Less important to some, a glass front would also present a more professional display finish like you see in high end commercial set-ups as well as protecting the fabric from scratches, kids and cleaning ladies who are all enemies of screen surfaces.

The problem with high ambient light is that projectors rely on darkness to produce blacks (we have solved for this by using a black screen), and glare off the surface that blocks our view. The latter is rarely addressed in a major way because most screen / projector combos would fail way before the room got bright enough for glare to be the reason the image fails. Using a black surface address the major barrier so it seems like a logical leap to look at ways of reducing glare for further improvement (selective reflectivity is another but that's another thread).

I did some research and have ordered around $300 worth of samples that include:
  • Anti reflective glass
  • Anti glare film
  • Anti reflective / anti glare plexiglass
  • Anti glare diffuser glass
  • Custom LED display glass with embedded optical lenses
  • Tinted matte reflective plexiglass
    Scratch resistant anti reflective plexiglass


My theory is that it will offer greater benefits than micro louvers without affecting image clarity and viewing angle (as the louvers do). The louvers were ineffective at stopping glare in my opinion on both the black diamond or the louver film I tested at home (I know louver film is not intended as a glare control method directly - they just attempt to block the light all together from a direction). Blocking light from above sounds better on paper than it looks in reality. Again, just my opinion / observation, but it added little that I didn't already have from using a black screen surface.

I am not sure why SI opted not to add a separate anti glare surface. It defiantly wasn't because they are trying to save on cost. I think it is more likely that they didn't consider it because the potential benefits only become obvious once you reach a certain level of ambient light performance ( ie in conditions bright enough for glare to be an issue). Perhaps it is easier to say, most screen set-ups don't let you get bright enough for glare to be the major issue. Washed out images normally make the set-up not viable first (before surface glare).

I can't wait for the samples to arrive so I can start testing them. This is the last phase of the black screen project - getting the build quality and design to a level that is comparable or better than the high-end commercial offerings. Preferably in a way that doesn't require me to become a carpenter. An anti-reflective/ Anti glare / scratch resistant glass layer at the front would add to that high end plasma look and make it look like a commercial screen.

There is a question around the point at which the cost of extra layers stops it being viable as a DIY offering. Finishing a large screen with a piece of anti-reflective / anti glare plexiglass will add $100 -$250 to the project costs. While this still leaves it way below high end commercial offerings, some would rightly point out that it is firmly within the territory of low end commercial grey screens. The extra layer certainly isn't necessary as the black-screen looks great without it. Even some of the $5000 commercial options don't have it but I want it to be the best that it possibly could be and I think this layer will make a small but noticeable improvement in higher ambient light conditions.

As an FYI, I have seen options for anti glare / anti reflective plexiglass for $5 - $9 per square foot. Testing will identify if they can double as diffuser or tint layers. One of the samples I ordered is a tinted charcoal plexiglass diffuser with a 25% light transmission which is perfect. It could potentially act as the rigid flat layer, the tinted layer and the diffuser in one. If it works, it would reduce the number of individual layers and take the cost back down to where it was before.

If anyone has any experience of anti-glare / anti reflective films or glass for use in screen surfaces, I would love to hear about it. Assuming we are talking about the appropriate matte finish transparent options that have a chance of working. When I say transparent, I do not mean like the diffuser films which are color transparent but hazy overall. The glass and film options I ordered claim 97% light transmission and glass like transparency (albeit with a matte but very much see-through appearance). When fixed to the front of the screen, the image should go straight through with no reflection, hot spots or glare. They should also block glare from other sources (like the sun) from reaching the screen layers underneath.

I will post results when the samples arrive and will report back on the claims that glare can be reduced by 97% without sacrificing optical clarity. We'll see!
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post #105 of 404 Old 10-20-2013, 04:39 PM
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Cost, complexity of build, and the readily availability of materials (...and the number thereof...) all certainly play into whether a DIY Screen design is viable for mass "cheapskate DIY" consumption.

Any example that exceeds $350-$400.00 will meet with some stiff resistance. The fact your potential offering is supposed to be comparable to a +$3K Mfg Screen helps, much the same as it does when Silver Fire is considered, so at least you have that going for your efforts.

The real truth being that a majority of DIY'ers seem to have a self imposed limit of under $100.00, with a smaller minority willing to up that to $150-$200.00

At even slightly higher levels, it starts to get to be a choice between a "el' cheapo Mfg Screen" and an advanced DIY Screen, but even then....$250.00 is close to a "top out" figure. Figure 10% of the cost of a comparable Mfg Screen and your at the "buy in" level most DIY'ers aspire to.

All that said, the potential shown in your results HAS to count for something....even within a limited scope of potential DIY'ers.

To quote James T. Kirk;
"I'm laughing at the superior intellect"
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post #106 of 404 Old 10-20-2013, 07:00 PM
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Quote:
Originally Posted by New Design View Post

Here is the same shot with the lights off. Note how the reflection off the white walls makes the room brighter You can see why nerds paint their walls black:

Is it really necessary to insult people who prefer a different screen solution to you? Especially when you have no idea what the people you are insulting are like. Some of those "Nerds" you refer to fly supersonic jets and engage in extreme sports that would leave you quite dead if you tried to follow them for an hour. I've enjoyed your posts to date, but if your only answer to minor disagreements is a personal insult then you might want to look in the mirror before you make disparaging personal remarks about others.
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post #107 of 404 Old 10-20-2013, 10:04 PM
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I don't think he necessarily meant that as a pejorative, Kirnak. Sometimes nerds call each other nerds, you know... I mean consider the source, right?
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post #108 of 404 Old 10-20-2013, 11:33 PM
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Maybe you're right Dennis, and if so I humbly apologize to New Design.

It's a button with me I guess. A good buddy of mine, a kid I grew up with from kindergarten, was bullied relentlessly in high school. "Nerd" was a very derogatory term at the time; it was pre-"Revenge of The Nerds". So, every time some one called him a nerd, I had to beat some heads.

Funny how things work out for the best though. Because of all the fights I was in, I became pretty darn good at it. That saved my life during a kidnapping attempt in Malaysia. And Steve, well he's worth many, many, millions of dollars.
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post #109 of 404 Old 10-21-2013, 06:28 AM
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New Design,

Please re-relate to everyone the type PJ your using, as well as it;s lumen output.

That has a great deal to do with your shown results, and should someone later attempt to achieve the same results using a 2000 lumen or less PJ, they just might call you out for not relating that your results show the way they do because you have in excess of 3K lumen.

Not being critical mind you....just letting you know that such things are to be considered inevitable.................and avoided. biggrin.gif.

To quote James T. Kirk;
"I'm laughing at the superior intellect"
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post #110 of 404 Old 10-21-2013, 04:35 PM
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I found a distribuitor of the light diffuser film that you use, in Europe, the film calls optigrafix , a product of graphics plastics and there is a distribiutor in germany. Do you use the DFPMET or DFPMHT film?What it will be the diference in performanse between the two? Like i said before in PM i am thinking using the 2.8 gain screen that i have as the reflective layer and like you advise maybe an window tint with 50% or maybe even less if possible like 70% shade. The final screen is for use in a dark room. The objective is to treat the secondary reflections and enhanced the perceived constrast mantaining a very bright image. Any more advice? If we use an reflective layer of 2.8 gain, a window tint layer of 50% and a difuser layer of 99% light transparency, the 3 layer screen become 1.4 gain and if we use an window tint of 70% the screen become an 2.0 gain, I think if i count it correctly!
http://www.optigrafix.com/light_diffuser_film.htm
Thanks
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post #111 of 404 Old 10-22-2013, 05:41 AM
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I feel the "Gold Standard" will result from the choice of a high gain dark substrate and the correct choice of overlaid diffuser. The simplicity of that solution should hold down costs, and make it a widely available option.

Multiple layers, expense, and more exotic substrates will only serve to limit the potential to a wider, needful constituency. DIY that is too complex (...and especially expensive...) becomes an exercise in frustration and is more often given a "Pass" by recalcitrant and wary DIY'ers.

My take, and not necessarily in keeping with what might be the inevitable solution.

To quote James T. Kirk;
"I'm laughing at the superior intellect"
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post #112 of 404 Old 10-22-2013, 10:50 AM
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I contacted the above and they not ship the require size that we need, i need 107`` by 60`` and they only sold for 60`` 3000 meters long, so almoust 400 dolars on the diffuser. I have to see a good alternative, what do you think?. I am thinking that with a good reflective layer we need a thinner and more translucive diffuser, and with a lesser reflective a thiker and more reflective one
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post #113 of 404 Old 10-23-2013, 03:07 PM - Thread Starter
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I don't use the optigrafix diffusers in my screen, I favor a PVC diffuser which can be wiped down for cleaning. I do have a folder full of samples and 2 full rolls of 25 yards. The two rolls I have are a 0.004mm single sided and a 0.004mm double sided. The single sided 0.004mm is the right choice for a black -screen project in my opinion. I tested every option in the folder.

The choice has little to do with the quality of the reflective layer and more to do with your choice of dark layer and the brightness of your projector. It is there to serve 2 roles. The first is to stop not spots which all of the films from that supplier would do. The 2nd is to give a lift in brightness by taking some of the burden from the dark layer as the screen surface.

My dark layer is a diffuse surface so technically I don't need an additional diffuser but without it, the image would be too dim (although still visible). It acts like a front and rear projection screen in one. Each layer will reflect a portion of the light and let the rest pass until it reaches the reflected layer where all remaining light is sent back to the viewer catching the diffused layers a 2nd time. If the middle dark layer has tool little light transmission to allow enough to reach the reflective layer, then the front diffuser layer will need to be a little thicker so less light passes and more of the image is reflected off the surface. The downside is that would also make you lose some of the dark appearance as a thicker difuseri is also whiter.

The ideal is to have the thinnest and most transparent diffuser that your set-up can stand. The next priority is the darkest black layer it can stand. All scenarios should include the most reflective back layer you can find. Just make sure you don't use a glass mirror -it has to be first surface or the image will be distorted. I use Mylar currently which work well, orcagrow also works. If you have some thing more reflective, that will be better still but it has nothing to do with your choice of diffuser as any diffuser shoulder move hot spots as a minimum.

If you use a single layer of 50% tint, it will not look black enough for most people's tastes. In my set-up, 2 layers of 50% tint worked well and looked very black.

More layers helps improve its resistance to ambient light as only directed light really passes through the surface layer in a major way. The number I have in my head is 25% light transmission for the dark layer. This was the minimum level that seemed to work with any projectors. I tried a 7% transmission tint and even the brightest installation projectors struggled. If you have a super bright projector, a 15% tint would probably work. As the tint comes in rolls, buying enough for 2 layers isn't normally too much more expensive and it gives you options. Try 2 layers and if it works, great, if not, use one. The ideal is to get samples and test it in your environment before buying a roll.

I would say that the quality of the first layer makes a larger difference than one might think. My PVC diffuser has good reflective properties of its own and lets me get away with darker middle layers.

A choice between 1 25% layer or 2 50% layers may sound the same but the 2 50% would look darker even though the overal light transmission may be comparable. In my screen, I use charcoal rear projection material which is another PVC fabric. Which one you choose is really down to taste as both will work. The tint has the advantage of being easy to attach to plexiglass which can double as you rigid layer to give a proffesional looking finish.

Don't worry about finding specific brands of diffuser. Anything that works is fine and there are tons of options. I find more every day. There is no guarantee that I have found the best yet. I am learning more about them all the time and have found some interesting stuff. I am going to post some info on rigid anti glare layers soon.

On questions about the impact of layers on gain in a specific way, there is no way for me to answer. There are too many influencers. Adding a 50% tint to a 2.8 gain reflective layer may sound like an easy calculation but I doubt it is as intuitive as that. All layers will have a degree of reflectivity on their own as well as degrading the reflectivity of the next layer. Don't focus too much on gain, it is not the main priority for this kind of screen which uses contrast as the primary mechanism for ambient light performance. Using a super bright installation projector on a high gain white, grey or silver screen will still look washed out in brite conditions. With direct light, it could look even worse. Projectors need darkness or a dark surface to produce blacks. That is 90% of why they look washed out in bright rooms. With the black menu page on my Sony Blu Ray player, you can not even tell that my 7000 lumen projector is on with a high gain white screen. A silver screen with an even higher gain is not much better. My 700 lumen projector on the other hand shows the black menu screen very well with the lights on with the black screen. I think the quality of the brightness also plays a roll. The Mylar has a retro reflective effect that directs the brightness towards me and making better use of whatever brightness there is.


On finding sources for materials, screen size is a limiting factor so you are better off with a wider screen. Finding materials in rolls up to 55 inches wide and any length you like, is easy. After 55 inches wide, your choice starts to shrink rapidly. I think you would find a 60 inch wide roll with some searching but thn you will probably be in the more expensive territory of larger commercial screens. A 150 inch 2.35:1 screen less than 55 inches wide and that is large enough for most living rooms. Larger than that is normally in dedicated spaces where light control is possible and there is less need for a black-screen.

You can tell that the commercial screen manufacturers have similar issues at the largest sizes. The price difference between a 115 inch screen and a 160 inch screen seems disproportionate to the amount of extra work involved in making them. Probably because you are in the teritory of custom runs at niche sizes. Good luck in ding the sizes you need and don't ignore theater supply shops who use many of the same materials we need and are used to paying far less for them. Also, commercial plastics companies who make optical substrates for the display industry can be a good source.
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post #114 of 404 Old 10-23-2013, 03:49 PM - Thread Starter
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My first piece of non-glare plexiglass arrived today and I did some testing. This isn't the stuff I'm excited about , just some glass from Home Depot that is used for picture frames. It's glare reduction properties are claimed in the 80% range which is not enough for our purposes. The ones I have high hopes for claim a 97% reduction. They arrive at the end of the week.

On inspection, the non-glare coating looks like mild etching. The glass is not see-through when you hold it up but it is see-through when placed directly on top of something, like a screen for example. This is different to non-reflective coatings which allow light to pass straight through. Non glare glass, just acts like a mild light diffuser and is therefore redundant in the current black-screen design.

Placing it in front of my screen does increase the brightness of the image but not without a faint hotspot.

On Lcd screens, polarizing films are attached to the front glass which will have a non-glare or non-reflective coating depending on how expensive the display is. Behind that, they have their diffuser films but not as the front surface like the black-screen design. The glass or acrylic hard coat in an LCD display is there to protect and hold the delicate polarizer films which are too thin to be there without the hard coat. The layers are stuck together with a transparent adhesive which, however good, has a negative impact on light transmission and reflectivity. It is just a necessary evil in that design.

I was trying to understand why I thought my screen looked brighter and sharper than the black diamond 1.4 gain screen I saw in Best Buy. Perhaps the Epson 5010 wasn't up to the task. Perhaps I am biased towards my screen. My nature is more to find a way of replicating something I like rather than pretending I already have it. Based on my research, I came up with a 3rd possible reason.
At the same time, I was also trying to understand why commercial screen companies seem to have their diffuser films in a different order. I think the answer is that the hard coat they use is a less effective anti glare layer but stronger than their diffuser and polarizer films. Also, the adhesive require to hold it in place is reducing light transmission. The difference is small but noticeable. For them, improved build quality for a small drop in performance seems like a reasonable trade off. They can't exactly send you a screen with visible staples holding the layers together and no hard coat. Even though the staples are at the back and can't be seen when its on the wall, at $5000, I want it to look great from every angle. I have been working on an adhesive option and have found some that do not bleed through but none that don't degrade sharpness and I have gotten used to the quality of image I have now.

The diffuser film is like an enhanced antiglare layer with double the glare reducing properties.. If I am to add a hard coat, it is going to have to be the more expensive non-reflective glass or a rigid diffuser. I will post some pics in a little while of the effects of the anti-glare glass.
I am thinking of using both a rigid diffuser and a rigid tint layer. I could then screws hidden by a thin frame instead of glue as a better solution. I can source plexiglass diffusers for a price that could work and in sizes up to 140 inches long. It would double the diffuser costs but a DIY project to make something that otherwise costs $5000, has a little more head room.

Has anyone got any other ideas as to why they put the diffuser behind the tinted layer? I would also like to know if anyone has a view on adding a circular polarizer layer? They are meant to only allow light from the right direction to pass but in a projection screen, that sounds like it could be trouble. Some commercial screens do have them though....
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post #115 of 404 Old 10-23-2013, 04:26 PM - Thread Starter
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Here is a pic of the anti-glare glass:


It almost looks frosted but when you place it on top of something, it becomes transparent. Here is a pic of me placing it on my screen:


In the pic, the room lights are on but it's the evening so there is no sunlight. The side covered with the non-glare plexiglass looks a little brighter. Here is a closer look:


If I turn the glass around and use the non-coated side, you can see through full hot spot to give you an idea of the difference made by the coating:


Being only a mild diffuser, even the coated side gives hot spots although they are less defined. We'll call it, the glare caused by the anti-glare glass (anyone else see an issue with that?):


I think that is the effect that reviewers complained about in the original black diamond screens. This affect can be reduced by tilting the screen but then you are also re-directing the brightness away from yourself. I remember people who went to the trade shows when the first came out were saying that they screens were all tilted down - a trick that also reduces the washout cause by overhead lighting.

Here is another pic to show the difference in brightness:


I don't think the increase in brightness is coming from glare reduction, just the reflectivity of the plexiglass. It only seems to apply to white imagery and also comes with a slight drop in detail but not enough to see from a normal distance.

The lesson here is that any hard coat like this is going to have to be the higher quality 97% options. Most of the ones I saw in suitable sizes were the higher performance ones luckily. I have higher hopes for the non-reflective scratch resistant options. We'll see...

The commercial designs seem to borrow the order from flat-screens where the image is coming from behind. Our image is coming from the opposite direction and can therefore get away with a less see-through and higher performing diffuser. I didn't realize that non-glare coatings were so similar to diffusers or I would have focused only on non-reflective glass for the tests.
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post #116 of 404 Old 10-24-2013, 04:02 AM
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I think the more reflective the diffuser layer is, the more secondary reflections we will have in the room, more light come again into the screen and kills the contrast, maybe thats why BD 1.4 use the tint layer in front and the diffuser in the midle, the difuser in the midle can be more thiker and double sizes and becomes not only a difuser but also a reflective one, and the screen becomes more blacker. After some tests in my room with a retroreflective vs a neutral screen i realize that a neutral fires the light to all directions, the retro reflective fires the more percentage of light back to where is the light is coming (i know most of you already know that...smile.gif), the perceived contrast of the 2.8 gain retroreflective survace is Better than a neutral 1.1 gain surface, so my reading is that the first layer has to be or the diffuser but with 99% light transparancy or the tint layer to not reflect anyting back to the walls and ceilings. the more thiker the difuser more light is reflected back to All directions and the difuser becomes, with less percentage of course, like a neutral screen. There are difusers than can reflect back 33% of light like the double sized ones, the single sizes and thinner ones almouts all the light passes true it and if we have a retrorefklective layer behind the tint layer the light is reflected back to the souce and we could kill all the secondary reflections. About the tint layer, the more tint less light pass true it, if the tint is 50% it lets pass 50% of the light that is coming from the projector right? The percentage of tint is dependet of the brightnees of the projector and the reflective properties of the reflective layer. Usually the brighness mode dont have the best colors so performance vs blacker screen...
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post #117 of 404 Old 10-24-2013, 06:58 PM
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the P90 i talked about earlier did the exact same thing your sample is doing.
it's too thick... and for a non hot spot image... it only be projected on the coated side.
your sample also exhibits the graininess of the manufacturered coating.
i can only see this working if hard difuser is 1/8" thick or less and if the difuser is embedded/extruded within the acrylic...rather than coated one side or the other.
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post #118 of 404 Old 10-25-2013, 02:52 PM - Thread Starter
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Quote:
Originally Posted by pb_maxxx View Post

the P90 i talked about earlier did the exact same thing your sample is doing.
it's too thick... and for a non hot spot image... it only be projected on the coated side.
your sample also exhibits the graininess of the manufacturered coating.
i can only see this working if hard difuser is 1/8" thick or less and if the difuser is embedded/extruded within the acrylic...rather than coated one side or the other.

That makes sense. I went back to Best Buy yesterday to take another look at the Black Diamond surface. Depending where I stood in the room, I could see a noticeable hot spot. It wasn't a defined reflection of the lens like you get with uncoated glass, it was a semi diffused area of surface glare.


It was hard to capture properly in a pic with my Ipad. As I moved around the room,the place where it appeared on the screen moved too. My sample of better anti glare glass arrived for testing yesterday too. It performed a lot better than the Home Depot picture frame glass. The new sample is designed for displays and, while not immune to the problem, performed well enough for some people. It was similar to what I had seen with the Black diamond surface. Here is a pic:


I think it might ultimately come down to a choice between installing a hard coat for it's aesthetic and protective properties or leaving the diffuser as the front surface for additional performance. With a slight increase in brightness from the anti-glare layer, also came a reduction in viewing angle. This was noticeable in the Black Diamond screen too (depending on the angle of the ambient light). Here is a pic of the Anti glare glass on top of my screen:


The manufacturer I went to specialized in custom optical coating and contrast enhancement filters etc. One of the other products they sold was a rigid diffuser with an anti reflective coating. This performed well although it was noticeably not as smooth as the anti glare glass:


The hard diffuser would have the added benefit of replacing the diffuser film from a cost point of view. The sample I tested was a little too thick for my taste and lost some of the appearance of the dark layer underneath. in a room that wasn't super bright, this seemed to make little difference to performance:


The pic above shows the hard diffuser with my black screen material behind it and mylar as the reflective layer. Like other diffusers, it also functions as a rear projection screen. It is far cheaper though, than any rigid rear projection screen normally sells for:


The great thing about custom manufacturers, while straying from the purity of a DIY project, is that you can get commercial grade materials and in some cases, access to technology that even high end commercial screens don't have. For example, this rigid tint layer, is designed to get darker as ambient light increases and lighter in dark conditions. Theoretically, this could give you the best of both worlds:


The material was matte on one side and glossy on the other. Like the rigid diffuser, it also functioned as a rear projection screen and a nice looking dark one too:


Other materials included a custom enhanced reflective layer. Well 2 actually. One looked suspiciously like a mirror and the other was like a smooth frosted mirror. The manufacturer said they were designed to enhanced RGB reflectivity but I couldn't say one way or another. The smooth frosted reflective layer was diffuse enough to function as a super bright screen on it's own but it was too bright to get a good pic of. On axis, the camera just captured a flash of light and off-axis, it directed all the light away making it look dark.



On the reverse of the reflective layers, was a "high contrast enhancement layer"


Projecting directly onto it gave a decent image but it worked better in conjunction with other layers.

Combining these materials allowed me to test an all rigid layer screen. I could see several advantages to that as well as some disadvantages. for example:


My thought on finishing the screen with a design to rival the appearance of commercial offerings was to retain some of the fabric layers and use only 1 or 2 rigid layers. Ideally, these would be at the front and back. On the other hand, an all rigid screen could be modular so I could switch layers for different conditions, types of content or future upgrades. The other advantage is that they can be joined with screws to avoid using any adhesive which detracts from performance.



The pic above has a rigid reflective layer, rigid tint layer that darkens as light increases and a front layer of anti glare glass.

I plan on doing some more testing and ordering some larger samples to how much it would cost to create an all solid commercial grade black screen. An option which I avoided for now, was the high-end and expensive anti reflective glass. This is a clear glass that should allow 98% of the light to pass instead of the 92% that regular glass transmits. The price for a single sheet in anything like the size we need for a projector screen was $1400. I may find some cheaper at some point but at that price, it isn't worth it. You would think it would be included with the $5000 commercial screens but even they consider it to be too much of a drain of profits. If I ever release a commercial screen at that price, I promise to use to high-end expensive glass!

The question may remain, are the benefits of a hard front surface worth the trade-off in performance in other areas? Other than transport, how much risk is there of damaging the screen? On the other hand, the anti glare glass offers a slight increase in brightness and clarity. it also looks high-end.

btw, embedding the diffuser inside the glass would not solve the issue if the surface remains the same. It is glare off the surface that causes the issue as it functions as a less diffuse and therefore less effective diffuser. If the commercial screen manufacturers borrowed the design from flatscreen TVs, it would explain the oversight as the don't have to deal with the directed brightness from a projector on their surface - their light comes from the other direction and hits a diffuser before it reaches the front glass.
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post #119 of 404 Old 10-25-2013, 03:25 PM - Thread Starter
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Here is another pic of the anti glare glass on my screen:


The anti glare glass is covering the bottom left corner up to half way across the Sherlock Holmes icon. I tried again with the brightness turned all the way down which made the brightness difference between the hard coat and non-hard coat area more noticeable.



The hot spot was mostly gone with less brightness although it was impossible for me to capture this in a pic. For some reason, I was seeing a hotspot on the camera screen that wasn't there is reality. I guess you'll just have to take my word for it. I remember reading something in one of the black-screen reviews that said the "hot spot problem" was only noticeable with brighter projectors.

Here is a pic of the black screen materials in use after being sealed with the transparent adhesive they sent me:


It was fine for the first 2 layers but I am not sure about the diffuser. Perhaps it will be better when all the air has worked its way out but I'm sure i can detect an additional texture from it which I don't love. More testing to be done on that one.
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post #120 of 404 Old 10-26-2013, 09:03 PM
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New Design, is this the kind of stuff you are talking about?

http://www.chameleonfilm2u.com/index.php/products/residential-series
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