SI Black Diamond clone? - Page 4 - Home Theater Forum and Systems - HomeTheaterShack.com

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post #31 of 47 Old 08-07-13, 11:06 PM
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Re: SI Black Diamond clone?

I can get some pics of the two side by side. As it stands right now. I prefer the look of the dynaclear if I am directly in front of it. As soon as you move a little off center, I prefer my diy mix. I won't be able to tell properly until I'm done experimenting and make my finished screen. The sony is really smooth and I won't get that kind of smoothness with the diy until I make a fabric version. Paint is never going to be as smooth. Also, Sony is only 80 inches and curls at the edge. If I could get the material, I would make my screen out of it but I can't so diy it is.
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post #32 of 47 Old 08-08-13, 06:23 AM
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Re: SI Black Diamond clone?

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Daylightuser wrote: View Post
I can get some pics of the two side by side. As it stands right now. I prefer the look of the dynaclear if I am directly in front of it. As soon as you move a little off center, I prefer my diy mix. I won't be able to tell properly until I'm done experimenting and make my finished screen. The sony is really smooth and I won't get that kind of smoothness with the diy until I make a fabric version. Paint is never going to be as smooth. Also, Sony is only 80 inches and curls at the edge. If I could get the material, I would make my screen out of it but I can't so diy it is.

I believe too that Dynaclear does a pretty good job in both environments with all of its pros and cons. As you, i couldn't stand the curve on the edges, so i cut it off and and i am going to attach it on a laminate or something like that using an adhesive two face tape. I don't think that i will resolve the hot spot problem but at least weakened a bit the effect. As far it concerns its performance, there's a sparkle problem on high brightness scenes and the over glass sensation that gives a kind of weird look at the image. On the other side, it is still a mystery, at least to me, how they achieved a low profile like that (i assume that the surface should be primed first and the painted) and what type of paint they used.
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post #33 of 47 Old 08-08-13, 07:23 AM
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Re: SI Black Diamond clone?

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Daylightuser wrote: View Post
I can get some pics of the two side by side. As it stands right now. I prefer the look of the dynaclear if I am directly in front of it. As soon as you move a little off center, I prefer my diy mix. I won't be able to tell properly until I'm done experimenting and make my finished screen. The sony is really smooth and I won't get that kind of smoothness with the diy until I make a fabric version. Paint is never going to be as smooth. Also, Sony is only 80 inches and curls at the edge. If I could get the material, I would make my screen out of it but I can't so diy it is.
As I said, great work Rob, after watching your vids I'm convinced that your DIY formula is the best I've seen so far! When you say fabric version, are you referring to the experiments with tinted films & mylar we talked about erlier? What kind of light diffusing films are you using, 3M Diffuser film? I'd like to know how rough or smooth the film is. As I mentioned erlier, I tried with frosted film, not 3M though, and I experienced a shimmering / glittering effect, looked somewhat grainy.

I made a sample yesterday with a reflective /mirror film with a reflectance of 57%. The film is transparent, often used in office buildings for privacy but also to keep the heat out, anyway, I mounted the film on a piece of plexiglass and then I sprayed a matte coating on top. To prevent any light passing trough I placed a black fabric on the back of the plexiglass. The result was a light grey screen with a bit higher gain than my kingpin screen with a gain of 1.0, but also a bit sharper.

I'll get back to you later with some pics!

Last edited by Patrik; 08-08-13 at 07:29 AM.
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post #34 of 47 Old 08-08-13, 11:20 AM
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Re: SI Black Diamond clone?

I doubt they used paint on the Sony. I am guessing it is printed on a litho press and then additional layers added on some kind of digital press like an hp indigo. It you look closely, it almost looks stitched. Over the reflective material is a criss cross of darker lines. Perhaps over the dichroic reflective surface, the dark lines act as as a hexagonal louver on a tiny scale. It makes a great travel screen (not that I ever travel with it). It could have used a little fiberglass backing. I was thinking of using a layer of carbon fiber to keep it straight.

Btw, I found a places that has larger micro louver films at a price that doesn't take them out the market. When I saw the 17 inch 3m product for $300, I was starting to think that larger ones would stop it being worth it. The new place had 65 inch ones for $150 and offers custom sizes so I will get a quote.
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post #35 of 47 Old 08-08-13, 11:34 AM
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Re: SI Black Diamond clone?

I was using a translucent rear projection material which is similar to the 3m product but a lot cheaper. I haven't taken delivery of my 35% tint material yet or the reflective film. The fabric version pictured only has a fabric front layer. The tint and reflective layer are made with paint in this version. In terms of image quality, it is most important that the front layer is smooth. The light diffusing effect on the material I used had no visible hot spots but I wont know for sure until I make a larger version and watch from a normal seating position. I could use an assistant to get better pics....when it comes to hot spotting, it can normally be solved by repositioning the projector on a different plane. Of course this isn't possible with some retro reflective screens so the quality of your light diffusing layer will be key.

At some point I will make a choice on which features are most important to me. Projectors seem to be getting brighter while maintaining good contrast. I was looking at a device with 10,000 lumens and an 8000:1 contrast ratio. Home theater projectors catch up with the pro devices eventually. There will come a point where gain won't be an issue but we'll always need contrast from the screen with the lights on until they learn to project black. I remember reading a post on a science forum where someone was asking about making a darkness projecting device. Everyone made fun of him and said "they already made a device that brings darkness, it's called a light switch".
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post #36 of 47 Old 08-08-13, 11:44 AM
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Re: SI Black Diamond clone?

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mechman wrote: View Post
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.
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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post #37 of 47 Old 08-08-13, 12:43 PM
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Re: SI Black Diamond clone?

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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post #38 of 47 Old 08-08-13, 04:31 PM
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Re: SI Black Diamond clone?

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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post #39 of 47 Old 08-09-13, 01:57 PM
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Re: SI Black Diamond clone?

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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?

Last edited by Patrik; 08-09-13 at 02:14 PM.
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post #40 of 47 Old 08-12-13, 06:19 PM
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Re: SI Black Diamond clone?

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!
Attached Thumbnails
SI Black Diamond clone?-tint.jpg  

SI Black Diamond clone?-trans.jpg  

SI Black Diamond clone?-aluminum.jpg  

SI Black Diamond clone?-tog.jpg  

SI Black Diamond clone?-res-1.jpg  

SI Black Diamond clone?-hot.jpg  

SI Black Diamond clone?-just-tint-plus-alu.jpg  

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