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Things have moved very fast in this thread the last couple days!

I have a comment regarding the photos and vids. Using a 7000 lumen pj to show a black screen image that is very small - screen wise - would be very simple to do. I'd guess your screen size in a lot of your images is roughly 60" or less diagonal where your showing the materials. Meaning your fL at your samples is somewhere in the neighborhood of what? A little less 700fL? Even if the ANSI Lumen rating for this pj is off by a factor of 2, you'd still be hitting the samples with a little less than 350fL. No offense, but I could make most anything look good with those numbers. You could use a solid black screen and it would look good.

Several years ago at avs, a member named budXXXX (replace the X'x with numbers) announced his black screen wonder and showed pictures of the screen in action. Most folks thought that it was the greatest discovery ever! However it was really just a practical joke played by bud. He made a very small black screen and took macro shots of it very close to his pj. Small screens being hit with a ton of lumens really shows nothing.

I'll read through more of this today, but so far, I haven't seen anything that I would consider a breakthrough yet. :huh:
Check out the latest video showing the test using a 700 lumen projector. You can clearly see it is not a joke, or a really small screen. The screen in my pics is 80 inches and the projector in a lot of them is set to project wider than the screen (as if it were projecting a 100 inch screen). Other than posting videos that show the whole room (like I did) and showing how it works with lower powered projectors, not much I could do to convince. I guess I just don't care enough to go to the trouble of creating an elaborate joke. This isn't about an invention. That already happened. We are just trying to recreate it for less money at home. I only used the 7000 lumen projector for the Rosso black fabric after everything else failed.
 

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For the non-believers. If this isn't enough proof then I can only assume you are currently wrapping yourself and your home in aluminum foil because "they are listening".

 

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Check out the latest video showing the test using a 700 lumen projector. You can clearly see it is not a joke, or a really small screen. The screen in my pics is 80 inches and the projector in a lot of them is set to project wider than the screen (as if it were projecting a 100 inch screen). Other than posting videos that show the whole room (like I did) and showing how it works with lower powered projectors, not much I could do to convince. I guess I just don't care enough to go to the trouble of creating an elaborate joke. This isn't about an invention. That already happened. We are just trying to recreate it for less money at home. I only used the 7000 lumen projector for the Rosso black fabric after everything else failed.
No one ever said it was a joke, I'm just not seeing anything that is ground breaking to me. Regarding the screen, what size screen you have the pj setup to project at on the wall behind or wherever matters little. What matters is the size where you are placing the samples. It's pretty clear that the image at that point was no more than maybe 30" high. A 700 lumen pj still outputs roughly 60+fL on a 60" screen.

For the non-believers. If this isn't enough proof then I can only assume you are currently wrapping yourself and your home in aluminum foil because "they are listening".

Black screen proof - YouTube
That's much better. :T What are the measures for these samples? Are they neutral? And to be honest. it appears to be a very light gray screen/paint (around N9ish) versus a very dark gray screen/paint (around N6ish) sample. That's an apples to oranges comparison. I honestly wouldn't expect it to look any other way. :huh: I'd like to see it compares to a Neutral gray of similar shade in a matte or flat enamel finish. Dark will always look better than white in any well lit environment.

Two final things:

  1. I wouldn't label me a non-believer. I've been a believer in darker screens over lighter screens for quite some time - probably a bit longer than you have been. ;)
  2. Read the forum rules. I'll let the tone of that last post pass for now. But I won't in the future. Keep it civil! :foottap:
I like what you're bringing here, but you need to be mindful of the rules!
 

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The screen in the video is about 48 inches high. The sample is one of my earlier attempts and has several uniformity issues. Mostly related to my diy skills, or lack there of. There is a patch on the screen where I missed with the paint sprayer so it wasn't an even coat of the translucent layer. That is one of the main reasons why I am keen to replace the front layer with fabric for the final version to avoid uniformity issues related to my painting ability. Also, I used a black foam sign board which is 80 inches. I got a few of these for trial and error because they aren't heavy and are relatively cheap but they are not suitable for a finished product. They are hard to get a smooth surface on and worse, they curl up when you apply paint for some reason. I had to put a layer of paint on the reverse to stop it becoming a curved screen. It still isn't 100% flat but it is ok for experimenting.

For the final one, I want to use a piece of polished Aluminum sheet metal as the base material and take advantage of its reflective properties.

I just got pricing in from a supplier of light diffusing film specially designed for screens. The only problem is that the smallest roll is 50 feet. This will be ok for my needs but might be too much for a single use DIYer. It will cost about $150 for a 60 inch wide 50 foot roll. Split between a number of screens, that won't be too bad if it works as well as they say.

I have to choose between single or double sided light diffusion but I don't really understand what difference this makes for this purpose.
 

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The screen in the video is about 48 inches high. The sample is one of my earlier attempts and has several uniformity issues. Mostly related to my diy skills, or lack there of. There is a patch on the screen where I missed with the paint sprayer so it wasn't an even coat of the translucent layer. That is one of the main reasons why I am keen to replace the front layer with fabric for the final version to avoid uniformity issues related to my painting ability. Also, I used a black foam sign board which is 80 inches. I got a few of these for trial and error because they aren't heavy and are relatively cheap but they are not suitable for a finished product. They are hard to get a smooth surface on and worse, they curl up when you apply paint for some reason. I had to put a layer of paint on the reverse to stop it becoming a curved screen. It still isn't 100% flat but it is ok for experimenting.

For the final one, I want to use a piece of polished Aluminum sheet metal as the base material and take advantage of its reflective properties.

I just got pricing in from a supplier of light diffusing film specially designed for screens. The only problem is that the smallest roll is 50 feet. This will be ok for my needs but might be too much for a single use DIYer. It will cost about $150 for a 60 inch wide 50 foot roll. Split between a number of screens, that won't be too bad if it works as well as they say.

I have to choose between single or double sided light diffusion but I don't really understand what difference this makes for this purpose.
How polished do you want the aluminium sheet to be? Close to a mirror? If you are looking for a mirror solution, then mylar or shrink mirrors could be an option. Mylar reflects 96.6% on average compared to a ordinary household mirror that reflects an average of 90%. Shrink mirrors is basically mylar stretched over a frame and then heated, the result is a perfectly flat first surface mirror.

I guess your plan is following: Aluminium sheet > tinted film > light diffusing film, right?

How are you planning on mounting the tinted and diffusing film on the aluminium sheet? From the tests I've done I've only succeeded mounting the films on glass or acrylic glass, it's the only surface flat enough for the job. I found this diffuser film on ebay, it might do the trick. Have made any tests using tinted film yet instead of black paint?
 

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I am not sure yet on the aluminum. From the research I have done, there are a number of options which all have their own strengths and weaknesses. It seems like the initial finish and the coating have equal importance because without the right coating, a layer of aluminum oxide will form on the surface and degrade the reflectivity over time (not that much time).

I have never been happy with experiments I have done using mirrors as the reflective component for some reason. Intuitively, one would think that it would be a perfect choice as long as you have the right diffusion layer but my limited trials have never confirmed this. The mirror seems to add nothing to the brightness, let alone the type of results I expected. I don't know why yet. 2 ideas I had are: I wasn't using a first surface mirror so the glass layer may have blocked some brightness. The front layer was too dark to let enough light through to make a noticeable difference.

What confused me even more was that adding a non reflective black layer behind the front surface made a huge difference in brightness. I assumed this was more to do with contrast than gain. We'll see, I'm not done experimenting on the reflective layer yet. There is a good chance that I will add a retro reflective sheet in between the rigid aluminum and the tint. These are custom built solutions that offer 98% reflectivity in a uniform way.

Mylar is an interesting idea. I have heard it a few times. Normally 8 people answer immediately warning against it due to hot spotting etc. This normally kills the enthusiasm of the experimenter so I have never seem pics of where someone actually tried it and had a solution for diffusion. My immediate reservation would be the shimmer. The more efficient the reflective surface, the harder the light diffusion layer needs to work to deal with it. I intend to try it as well as the black diamond mylar foil (nothing to do with the screen innovations product). They sell rolls of it on ebay and it made me curious. If anyone has tried mylar under a diffuser, I would love to hear how it went?

A sample of the tinted film arrived today so I did some crude tests and immediately concluded that I purchased the wrong film for my needs. I got a metal coated version instead of the nano ceramic and it is too reflective for what I wanted. That said, my chosen diffusers haven't arrived yet so it may not matter.

Check out these pics. 1st, the film. This is a 35% tint charcoal film. Notice that it adds contrast without changing the color profile of the tv image. This is key to the experiment. When you work with paints, you need a fairly light neutral color to avoid a color shift or blocking reflectivity. Adding a tinted layer, that is designed to let light pass, behind a white translucent or transparent film, changes the appearance without color shifts. The dark grey, and probably not neutral appearance is actually 3 separate layers. Only the first layer has an impact on image color. A color that dark created with paint would probably reflect very little and be too dim to watch. With paint, you are relying on the top layer to do the job of all 3 layers. In this case, the tint lets 57% of visible light through unchanged. They are available with up to 99% transmittance and down to 0% so plenty of options.

2nd, for the purpose of this very crude test, the light diffusing layer is a piece of transparent projection film. Not the most efficient diffuser but fine for a crude test. 3rd, a piece of slightly polished aluminum. Note that this aluminum is not polished to a mirror finish. It is still somewhat matt and, to date, that is what I have had the best results with. Again I don't know why or if it is just user error which is equally likely.

4th, this is what is looks like with them held together. Almost like an off plasma tv. That description sounds familiar....

5th. Here is what it looks like when you project onto it. It actually looks great at the right angle. I thought the tint was too dark but now I'm not sure. I will try 50% and 70% to see but 35% isn't horrible as long as there is a diffusing layer that has some small reflective properties of it's own.

6th. Now here is the problem with the transparent film. Even with the matt side, if you position it at the same angle as the projector, you will see a hot spot from the reflection of the lens. Now, you could deal with this by clever positioning of the projector. A ceiling mount pointed diagonally down and some keystone correction will work but, it would be better if it wasn't a problem at all. kinda like a hole in your pants that only you know is there. Not everyone can live with that once they know.

7th, just so you can see what the diffusing layer is doing, here is a pic of what it looks like with only the tint and the aluminum. Ok if you like to watch your own reflection at the same time as the movie.... but not usable for most.

I have a feeling that trade off between a smooth surface and high image quality vs a texture and no hot spotting will end up being the biggest challenge for this project. I need to do more research on how to eliminate hot spotting without losing resolution. Hot spotting is a complaint with the black diamond screen so if I wanted an authentic copy, perhaps I should leave them in..... I have a feeling the 50% anti reflective, non-glare nano ceramic film will work well when paired with the light diffusing film I have ordered. It is said to be far less reflective and has a non-glare treatment.

I saw some options for diffusion film on ebay but nothing that was the right size at a price that works for a diy project. One could end up paying so much that they could have just bought a finished screen that did the job, so finding a low cost option is important. The one I have ordered is designed for screens specifically and will drop the price down to $30-$40 per screen. It comes in 25 foot rolls so I will see if there is a way of splitting it between a few people here (if there is a way of doing that which adheres to the site rules). Lets see if it works first!
 

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You either need a better camera or you need to learn how to use a camera better. No offense but I have yet to see a good picture from you. And as for the materials/methods, we can't really judge them by your pictures I hope because again, I have yet to see anything that looks good. :huh:

Are you using a cell phone camera? I can't tell because there is no EXIF data in your pictures either.
 

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On the pics in the last post, I wanted to ask if anyone had tried a hybrid approach for rear front projection.

Normally, rear projection is only possible where there is sufficient space behind the screen. For a non-DIYer, it is also dependent on the willingness of the user to pay $10,000 for a mirror on stilts to go behind the screen. One could be forgiven for thinking that some screen companies are a little out of touch with the market. Hard to imagine feeling like I had a good deal at that price. It's easy to see why the technology never became mainstream. You see them on ebay at that price. I always wondered if anyone ever bought one and was happy about that?

Anyway, I digress. I have found a manufacturer who claims to be able to supply a black screen fabric for rear projection and a very dark grey charcoal black front projection fabric. The latter looking similar to the black diamond 0.8 gain screen in color (only). I ordered 100 inch by 60 inch rolls of both. My interest in these is mainly for work (I have a displays business). But, it struck me that they may be relavent to this topic for obvious reasons. Rear fabric can sometimes work as front fabric if a reflective surface is applied to the back and the front isn't too glossy.

I see this DIY project as having 2 parts. One is the ambient light rejection component with the complexities of micro louvers etc. The second, which may be as interesting if not more for some, is creating a screen with that black or dark finish that looks stylish and offers a greater enhancement to perceived contrast than current grey options. Black does look more high tech and flat screen tv-like. The second component is relavent here.

Even though I prefer the look, I don't use a rear projection set-up at home because I don't have enough space behind the screen to get a decent sized image. My wife would also be unhappy if I knocked down the wall separating the living room and our bedroom (even after seeing the improvement in contrast! I know, I know...)

The price of mirror rigs has always seemed outrageous too. Even though I'm well off financially compared to most, I would feel like an idiot giving these people $10,000 for a mirror. I don't care how flat it is.

Over the weekend I was thinking about a hybrid approach where the projector and screen stay in the same place but I project down onto a mirror on the floor behind the screen and the screen is mounted on a stand like the "fast fold" screens. I did some mock ups of the concept in the images in the previous post. The 2nd coffe table positioning of the projector would be good for people who don't want to ceiling mount.

The screen could even be attached in between two book shelf units to create a dark space if the room is really bright or the projector very dim. Like a rear projection tv that blends into the room. It is a lot easier to make a black rear projection surface with no hot spots than making it reflective enough for front. It is also a more effective way of dealing with ambient light in the absence of micro embossed films and that's what this screen color is really about.

Now , I know the mirror in the pic is too small for the position of the projector etc but that is just details.

This method is also a good way of reducing the throw distance without buying an expensive short throw lens (which can cost north of $2000 on their own).

I have found a local place that can sell me a glassless first surface mirror that is lightweight and large enough to use on a 120 inch screen with very little space. It even comes on its own stand on wheels that makes it position able at the right height and angle. It can be cut to a different shape for tight angles and costs less than $400 for one that was 8 feet wide and 4 feet high. $400 sounds like a lot for a DIY project you could say. True, but 10 times less than a comparable sized optical mirror from a well know screen manufacturer. For the more daring, they also sell a DIY option that you shrink onto a flat surface using a hair dryer. This apparently gives the same results if you start with a flat surface and do everything right. Assuming you have skills, $80 will let you make one of any size you could fit in your house (within reason). Btw, first surface, is a term that means a mirror that doesn't have glass in between you and the reflective surface like a bathroom mirror. That glass is a problem for this purpose. Some will tell you they won't work at all. In my experience, they will but you'll loose brightness and get brightness uniformity issues.

You can also get smaller but perfect used mirrors off ebay that have been taken from rear projection tv's. they seem to go for $40 - $120. You could buy the whole tv for the same price if you want to go get it. Interestingly, not all of the mirrors taken from these tv's are first surface. I don't know why but perhaps they came from inferior or older models?

Can anyone think of a reason why this couldn't work?

As a stop gap, I was also thinking of using one or two of my ultra short throw projectors set to rear projection. I could place them on the floor behind the screen. I have one that can give a 120 inch image with a little over 1 foot of space (less than the tv stand currently takes). Maybe it could be a pull down screen attached to a shelf to be invisible when not in use too. I use some weights at work that are designed to keep these films flat when used in a suspended role up design. I would probably mount the black material on some glass to give it that edgeless look. In my head it is some stylish glass with rounded corners with two holes in the top corners that allow it to be suspended with invisible string to give that floating in mid air, frameless look. I see no reason to make it look just like a tv which I see as an ugly black box.we don't have the same limitations so we can free the screen from the black box and create cool designs. Specifically taking advantage of the non-fixed screen size to allow a giant theater like screen for movie night that doesn't dominate the room when not in use. Have you seen that Sharp 80inch lcd? The wife would never allow such a monstrosity in our living room.

I have no idea if either the black or charcoal fabric work with ultrashort throws. I know from experience that optical screens usually struggle. Glass beads, for example, suck with ultra short throw unless you sit on the ceiling.

As well as the front / rear idea, I would also like to know if anyone has experience with black rear projection fabric? I would like to know how well it performed. I have already been warned about a narrow viewing angle so there is one limitation but they all have that (except the draper high performance). I guess I'll see for myself in a few days.

Also, I would love to hear any experience with the da-lite 3d virtual black and 3d virtual grey. These seem to be indicated for 3d only. They are not claiming it is good for 2d. In fact, they suggest having 2 screens. I would love to know if 2d is at all watchable but with limitations or just completely unusable?

The fabric I ordered is nothing like the da-lite 3d btw. This is from a manufacturer in Australia who also supplies me with led screens from their facility in china. Their fabric is for 2d and 3d (active). The da-lite seems to have been released under the radar but seems to be a relatively low cost (for them) commercial dark screen. It is a shame if it only works for the one content type that nobody above the age of 6 cares about. You can buy it as a DIY fabric though. Perhaps they released it before everyone agreed that 3d wasn't the next big thing after all?

$800 will get you a piece to make your own decent sized screen. I find it hard to imagine there being much of a market for a DIY fabric at $800. Especially if it doesn't work for 2d which is a fairly large flaw by any standards.

They aren't the only ones with their heads in the clouds. I have a supplier who sells black optical fabric and fabric with micro louveredfilter filters for sunlight rejection. I had forgotten all about them. I became a reseller last year and then put their info to one side when they sent me their dealer pricing. A piece of the micro louveredfilter film to me was more than $2500 for anything over 100 inch. They expected me to add a mark up and sell that here even though they have no brand recognition in the US. I told them that I could sell one screen, even if I added no mark up at these prices.

It is no wonder projection has such a hard time in the mainstream. Clients will always look at a roll of DIY fabric at $2500 as an obscure product with limited application. With the price of pro projectors, they prefer the more reliable led screens which is a shame because all you see up close is a bunch of dots. Anyway. Enough complaining from me!
 

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You either need a better camera or you need to learn how to use a camera better. No offense but I have yet to see a good picture from you. And as for the materials/methods, we can't really judge them by your pictures I hope because again, I have yet to see anything that looks good. :huh:

Are you using a cell phone camera? I can't tell because there is no EXIF data in your pictures either.
I am using a cell phone camera. As an FYI, saying "no offense" before saying something offensive doesn't stop it being offensive. I don't have to post anything. I don't get paid for this.

They aren't the best pics but you can see, for comparative purposes the difference between screens. Now add something constructive or say nothing. I don't care about your critique of my photography. For someone who is so sensitive, you don't make much effort to be polite. If this forum has no interest, read another one or post something better.
 

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Just got some polyester mesh screen printing fabric. Works very well as a light diffusing layer and is cheap. $27 for a piece large enough for a 120 inch screen.

It works well as rear projection fabric too but our interest is for it's use as a translucent light diffusing layer. The results pics show it with a piece of dark tint - (actually an ipad privacy screen that also just arrived). Behind the tint is a piece of aluminum. All very crude as it only just arrived. More testing with better, larger pics tomorrow.
 

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Just got some polyester mesh screen printing fabric. Works very well as a light diffusing layer and is cheap. $27 for a piece large enough for a 120 inch screen.

It works well as rear projection fabric too but our interest is for it's use as a translucent light diffusing layer. The results pics show it with a piece of dark tint - (actually an ipad privacy screen that also just arrived). Behind the tint is a piece of aluminum. All very crude as it only just arrived. More testing with better, larger pics tomorrow.
Rob, I like what I see! I know you have no more than two hands, but it would be awesome to see a white board held up right next to your test with the iPad privacy film. Judging from the picture, it appears the test with the privacy film has somewhat lower gain than a regular 1.0 gain screen, on the other hand the surface is much darker. I've seen your pics from the glass bead test and it truly looks impressive! Wouldn't that work as a final screen? Any disadvantages?

Regards, Patrik
 

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Hi everyone!

I know the 3M Vikuiti rear projection film have been discussed here earlier, but got dismissed due to the fact that it wouldn't work as a front projection surface, but I found a vid on youtube were a guy walks behind a 3M vikuiti film and it still looks impressive.
A found this picture on a 3M retailer website >>



And this is how a glass bead screens works (for those of you who wonder) >>



It's very similar except the gloss layer in there between. 3M Vikuiti comes in rolls with a width of 47.24". I'm curious to see for my self! Have anyone tried this?

/Regards, Patrik
 

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With the mirror-diffuser-tint/darkening pattern, rear-projection has the obvious benefit where projector-light only needs to pass through the darkening layer once (instead of in and then out = twice for front projection). So rear-projection would allow more brightness(with same tint) OR a darker tint(and same brightness) compared to front-projection. Also, a less effective diffuser won't hotspot as noticeably until it's so thin that you're getting blasted with light in your eyes.

Mirrors for the rear-pro could be inexpensive to aquire either via secondhand stores or by making your own out of mylar over a frame. I don't remember if it's been mentioned here yet, but reflective mylar AND diffusing sheets can usually be found (affordably) looking for hydroponic/greenhouse supplies. Also, don't underestimate a $2-3 thin, frosted, showercurtain as a fun trial into rear-projection.

I wish it was easer to just find old CRT rear-pro screens that weren't cracked or didn't require you to also haul and then recycle a broken CRT TV. The cracked one I was fortunate enough to play around with had fantastic front light rejection AND side-to-side viewing angles. It's up/down angles were narrow, but they also don't matter to anyone who's sitting and watching the screen (you only need something like a 10degree arc).
 
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