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  Topic Review (Newest First)
08-08-13 05:11 PM
Daylightuser
Re: Glass sand-blasting beads in DIY screen

This is the text off their site:

Another front projection surface with high gain is Da-Lite's new glass beaded High Power™ material. Although glass beaded screens have been around for years, the High Power™ surface represents a substantial advance in technical excellence. The surface of High Power™ is comprised of a huge number of tiny glass beads distributed evenly across a white vinyl field. In constructing this surface Da-Lite has found a way to get the diameter of the average bead reduced to about 9 microns. This is better than a conventional glass beaded screen by a factor of 7 since their typical bead diameter is about 65µ. The consequent improvement in resolution is of course equally great.

I read a little about how they say it works but then my brain melted and poured out of my ear. I don't know if they make their own beads or buy them. The part I don't agree with is that it is better by a factor of 7 because the beads are 7 times smaller. It's too simplistic. Reading the rest of the page, they go on to explain in complex details about the difference the positioning and pattern of the beads makes. I have 3 sets of beads here. The powder sized beads are probably at least 7 times smaller than the next size up but they are not 7 times better because my eyes can't detect differences once you reach a certain size. Just like I can't tell the difference between 15,000:1 contrast ratio and 50,000:1 contrast ratio.

I am sure that Da-lite use better beads than my $5 experiment. From what little I do know, higher quality beads are not just smaller. You pay more for coatings, smoothness, consistency and the one that I understand makes the most difference which is the refractive index. For home theater, you would ideally want the 1.9 instead of the less expensive 1.5's. 1.9 index beads are 7 times brighter at a closer range.

I have also seen glass beads coated in pure silver which I'm think would be amazing but I haven't tried....

On the size issue, I have heard a lot of opinions on it. What is too big or too small (still talking beads!). I know one thing and that is, until you try it, you won't know if any bead will work for your room. My experience from experimenting is that once the beads get smaller than I am able to see without a magnifying glass, they are small enough to give a smooth surface that doesn't inhibit the detail of a 1080p projector.

Even the sand sized beads are only really visible if you are close. Check out these 2 pics. Both show a piece of black material painted with aluminum ink and then covered in sand sized glass beads. Using a 2000 lumen projector in the afternoon with the blinds open and lights on in the room. 1 pic is taken from a little closer than watching distance but directly in front. The 2nd pic shows the same except slightly off center. My biggest issue with this particular lot is the very narrow viewing cone. I also prefer the look of the powder sized beads for smoothness but at this distance, the glass texture is not massively prominent.

The overall point is that if you want to make a glass bead screen at home, you can. Information that suggests that it is impossible to get a consistent surface or find beads that work at all is inaccurate. There are tons of beads for sale on the internet. Literally hundreds of options from boron coated black beads to silver coated, to dichroic selectively reflective options. Some are expensive. Some are very cheap. I am fairly certain that if I put my mind to it, I could find beads that are both better and worse than whatever da-lite uses. Most of these screen companies are small niche manufacturers that often get away with charging a lot for a piece of material. Based on the limited innovation we have seen in this space and the number of industries that rely on reflection, the idea that they have a unique secret manufacturing process that is better than any of the dedicated larger manufacturers in the market is unbelievable to me. At least, could find any patents owned by them for beads.

Check out the reviews of the high power screen. They don't support their claims.

http://www.projectorcentral.com/da-l...een_review.htm

The part I took away was: "There are other picture attributes to be concerned with besides brightness. Black level, detail clarity, and color uniformity, to name a few" And more relevant:
"But most surprising was the fact that the Affinity looked smoother and sharper. Despite the fact that the High Power fabric has a very smooth surface, its picture had a graininess and noise level that was entirely absent on the Affinity".

The picture has a graininess and noise level. Not my words, just the words of someone who has actually seen it. Seems like the 9 micron beads weren't as good as they sounded on paper....

It's easy to be intimidated by the science on their websites. On face value, one could assume that it is impossible to make something nearly as good. That's what the marketing is meant to do. Scare you into thinking that $3000 for a piece of fabric is money well spent. The modern day emperors new clothes. They have all the same issue with glass beads that you or anybody else would. Just like them, selecting the right ones is a factor but no reason why you can't buy a bag of some that will work, just like they did. You're better than that!
08-08-13 03:33 PM
mechman
Re: Glass sand-blasting beads in DIY screen

There are magnifications of the High Power floating around the forum here somewhere...
08-07-13 08:16 PM
Harpmaker
Re: Glass sand-blasting beads in DIY screen

Quote:
Daylightuser wrote: View Post
The glass beads I was referring to are described as "powder" sized. There are 4 sizes I have seen. The next one up is sand sized which work but not great. The powder sized ones are small enough to give you a smooth surface that can't be detected at a reasonable watching distance.

I am not sure what is smaller than powder (except smaller powder I guess). In my opinion, once the glass is small enough to snort, it is small enough.

I can't swear they are the best or smallest available but they do work without leaving a visible texture. In fact, they are small enough that I get a smoother texture with them than I do with some paints.
You probably got your beads from " colediscount" on ebay. The other hits I got searching for "glass beads powder" were visibly larger. The Mil-Spec 10 beads are the smallest they sell. It's kind of funny, but their "Contractor grade" beads are larger than the Mil-Spec 10 beads but they are also smaller because their size range is greater (841 to 44 micron); but even the 44 micron beads are too large in our opinion.

Quote:
I have a feeling that Da-lite make a distinction between "having the effect of 9 microns" and actually being 9 microns. All the glass bead screens of theirs I have seen look rough and aren't that great but I haven't seen their very latest one which is the one you can wash etc. Have you seen the latest one by chance?
There is really no way I know of to have a reflective "effect of 9 microns" without having an actual reflective surface of that size.

Da-Lite has made many different kinds of retroreflective screens over the years and they are not all equal. I have an old glass beaded screen of theirs that my father used to project 35mm slides on 50 years ago and it has a surface that feels like some kind of rough animal hide due to the large size of the glass beads - definitely not good for use with today's hi-res front projectors. The Da-Lite High Power screen is another critter entirely, what it does it does well.
08-07-13 04:01 PM
Daylightuser
Re: Glass sand-blasting beads in DIY screen

I was excited for a second. I thought you meant a place where I could buy a roll of the dynaclear fabric. I already have the 80 inch portable sony screen. problem is that it's too small and badly made. The edges on these were famous for curling after a few seconds of ownership. You kinda get what you pay for I guess. It's a shame because the screen material is amazing. It's so clear and the blacks are so, well... black. It's a shame they never made a better quality larger version because, at that price range, I would never have bothered with any diy method as there would have been no point.

They claim it has a dichroic coating which, for the less nerdy readers, is a multi layered coating where each layers has different properties and is sufficiently thin to not block the properties of the other layers. For example, the most effective way to reflect red is with red pigment. The problem is that red pigment blocks green and blue which defeats the purpose. With this dichroic coating, they claim it is selectively reflective to only reflect red, green and blue light wave bands and nothing else. I can't say by looking at it that it is true or not. Well, not completely and projectors are not the only source of red, green and blue light. Either way, from directly in front of it, it is the best screen surface I have seen period. The only screens I haven't seen from the main manufacturers are the $25K DNP screens which I hear are amazing. They perform really well for the 4 people in the world who are stupid enough to pay $25K for a screen for their home.

BTW, that Alibaba is not a shop, it is a trade portal which, in theory, links manufacturers in asia with buyers here. In my experience from my other business, trying to buy anything through it is frustratingly risky. You get emails from people in China asking you to transfer money using western union before getting your products. It's like "sure, I'll transfer $20K into an untraceable cash transfer for someone I don't know in China. That doesn't sound at all risky". None of them take credit card or paypal and none of them give you a straight answer. if you ask for a price, they ask you how much you want to spend or what the budget is. The kind of thing that makes you want a shower after speaking to them. If they are honest, they don't act like it. I know it sounds like I'm generalizing, it's just that I had the same experience with more than 30 vendors across multiple areas. I have never had a good experience and wont trade until there is a secure payment method that doesn't involve untraceable cash transfers or escrow holders I never heard of.
08-07-13 02:16 AM
Daylightuser
Re: Glass sand-blasting beads in DIY screen

Thanks. I'm going to check it out. If they can supply me with that material, I will be a happy man.
08-07-13 02:07 AM
Daylightuser
Re: Glass sand-blasting beads in DIY screen

The glass beads I was referring to are described as "powder" sized. There are 4 sizes I have seen. The next one up is sand sized which work but not great. The powder sized ones are small enough to give you a smooth surface that can't be detected at a reasonable watching distance.

I am not sure what is smaller than powder (except smaller powder I guess). In my opinion, once the glass is small enough to snort, it is small enough.

I can't swear they are the best or smallest available but they do work without leaving a visible texture. In fact, they are small enough that I get a smoother texture with them than I do with some paints.

check out this link to a crude test I did:


There is a section at the bottom that I didn't cover properly but the rest looks smooth to me. I have a feeling that Da-lite make a distinction between "having the effect of 9 microns" and actually being 9 microns. All the glass bead screens of theirs I have seen look rough and aren't that great but I haven't seen their very latest one which is the one you can wash etc. Have you seen the latest one by chance?
08-06-13 08:52 PM
Harpmaker
Re: Glass sand-blasting beads in DIY screen

Quote:
Daylightuser wrote: View Post
Harpmaket,

I can't remember the name of the place but you can buy them off eBay for $5-$10. Just search for reflective glass beads powder and you'll see. Avoid the ones that say airport quality. They are tempting due to the promised 99% roundness but they are fare too big. The sand sized ones work but the surface ends up a little too rough for my taste. Powder is the easiest to work with ad long as whatever you use to stick it to the screen is a really thin layer so they don't sink in. At that price it is worth buying a bag to see if you like the results.
Thanks for the reply. What I found on ebay are beads that are "Mil-Spec 10" in size. This means the beads are anywhere from 150 micron to 89 micron in size. In my experience this is too large for projection screen use, but beauty is in the eye of the beholder. As a reference, the 2.8 gain Da-Lite High Power screen uses 9 micron beads. Also please note the photo below. The beads that look like boulders are ~50 micron, the glass beads they are resting on are of an unknown size (the manufacturer of the reflective paint wouldn't tell us), but they look like gavel compared to the 50 micron boulders.

08-04-13 07:58 AM
Yiannis1970
Re: Glass sand-blasting beads in DIY screen

Quote:
Daylightuser wrote: View Post

On the 3rd pic, number 1 shows my Sony Dynaclear portable screen. I love this fabric. I wish I could buy a roll of it to make my own screen. I tried to find who made it for Sony as I doubt they built a fabric factory for the 2 years this was on sale. I couldn't find who the supplier was. It isn't the brightness I love, it's the smoothness and therefore, the quality of the image you get. If anything, it can be a little dark. Like the glass screen, you have to be in front of it. From the sides, you wouldn't even know if it was on. 2nd is my custom black-screen fabric that I am working on. This is my favorite so far. The front is charcoal colored and the back is aluminum and then black ink. It is super smooth and gives great contrast. Still a work in progress though. 4 and 5 are my home made black screen which I love. I would only recommend this of you have or are prepared to buy a paint sprayer.
I have the same screen and i was trying to find out myself too!!

Take a look here:

http://www.alibaba.com/trade/search?...luminium+sheet

I believe this is the place to look up for Sony's Dynaclear screen.
08-03-13 07:46 PM
Daylightuser
Re: Glass sand-blasting beads in DIY screen

Harpmaket,

I can't remember the name of the place but you can buy them off eBay for $5-$10. Just search for reflective glass beads powder and you'll see. Avoid the ones that say airport quality. They are tempting due to the promised 99% roundness but they are fare too big. The sand sized ones work but the surface ends up a little too rough for my taste. Powder is the easiest to work with ad long as whatever you use to stick it to the screen is a really thin layer so they don't sink in. At that price it is worth buying a bag to see if you like the results.
08-03-13 07:40 PM
Daylightuser
Re: Glass sand-blasting beads in DIY screen

Ok from left to right: the first pic shows the conditions and the benchmark screens. 1 shows the open window. This is a large double window to the left of the screen. The 2nd pic shows the light which is on the ceiling to the right of the screen. I am using a less powerful 3000 lumen projector. I know this is still brighter than older home theater devices but some of the newer ones are approaching this level. 3rd is a piece of non-glare plexiglass with plain aluminum paint on the back. This was to compare some of the effort to one that required no effort. 4th, is my reference white wall screen. You can see that even with 3000 lumens, the pic looks washed out. The photo makes it look a little better than reality for some reason but you can still see what I mean. Most screens are designed to offer something that is somehow better than the classic white.

The second pic, again from left to right:
1 shows a piece of tinted window film covered with a layer of black paint and the covered with a layer of sand sized glass beads. I know it's hard to compare finished screens to small bits of fabric but I just wanted to see if it was worth the effort to make a full screen this way. It works ok, I think if I put in some time and effort to make it smooth, it would do its job. 2nd is a finished black widow screen. Well, a slowly enhanced black widow screen. I added some aluminum ink to the paint to up the gain slightly to make up for the loss associated with a darker color. I am a fan of this screen for home theater use. 3 and 4 are the glass bead screen I made with aluminum ink covered foam board with a thin layer of epoxy and finished with powder sized glass beads. 3 is what you see from the correct angle, 4 is what you see if you go too far off center. This is what retro reflective screens are meant to do. They work if you sit in front of your screen and not if you don't.

On the 3rd pic, number 1 shows my Sony Dynaclear portable screen. I love this fabric. I wish I could buy a roll of it to make my own screen. I tried to find who made it for Sony as I doubt they built a fabric factory for the 2 years this was on sale. I couldn't find who the supplier was. It isn't the brightness I love, it's the smoothness and therefore, the quality of the image you get. If anything, it can be a little dark. Like the glass screen, you have to be in front of it. From the sides, you wouldn't even know if it was on. 2nd is my custom black-screen fabric that I am working on. This is my favorite so far. The front is charcoal colored and the back is aluminum and then black ink. It is super smooth and gives great contrast. Still a work in progress though. 4 and 5 are my home made black screen which I love. I would only recommend this of you have or are prepared to buy a paint sprayer.

I have learned a lot from my tests and now I have some new ideas that I haven't tried yet. Specifically, it struck me that commercial screens increase contrast by using tint, not just darker paint. Technically, darker paint is a kind on tint but I think they mean transparent tinted material like the kind that is used for car windows.

I tested a theory with some window tint I had at home but it was only 20% transparent. This was too dark but it worked (to a point). For multi layered screens (as all the expensive ones are), the middle layers have to be transparent to allow the back layers to do their job. Essentially, you need a reflective layer, a tinted layer and a light diffusing layer at the front. Light rejection screens also have transparent layers printed with micro louvers to reject light from specific directions. The Sony screen claims to be selectively reflective but there is more evidence of it using light blocking technology given the narrow viewing area.

For my master screen, I am thinking about starting with a piece of polished aluminum sheet metal which will keep it rigid and act as the reflective layer. Then I want to try a layer of tint. Perhaps 70-80% transparent, just enough to give it contrast. The film also needs to be anti glare. Finally, a layer of semi transparent light diffusing material (or possibly paint. Finally, anti glare glass. If the projector is not at the same level as me for viewing, I think I will avoid hot spots.

I also looking at custom sized privacy filters. These use similar micro louvers to the black diamond type screens. They only let light pass for the front 60 degrees. For computers, they stop over people seeing your screen from side. I am getting pricing for a 100 inch version to test on my screen to see if I can recreate light rejection from the sides at home.

I think this method will make a really professional looking edgeless screen if done right. I will post some more pics when I try it, assuming it gives results that are worth sharing.

Rob
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