RGB Paint Mix Experiments & Discussion - AVS Forum
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post #1 of 413 Old 09-04-2006, 02:54 PM - Thread Starter
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post #2 of 413 Old 09-04-2006, 03:31 PM
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Well, you certainly want to open up a can of worms.

Ok, where do you want Me to start?

In the beginning, there was BF and the use of RGB pigments. In always wanting the best for ME; Me sprayed up some panels with Auto Air Candy Colour RGB. Layered application, first B, then R, then G. Looked like puke. Me then mixed up some Auto Air Hi Lite Interference RGB with various bases. Not bad. Had a pearlescent colour to the mix. Good gain, and good viewing cone if you made the mix translucent and laid it over a matte white basecoat. Aborted idea since they weren't really doing much for Me.

Idea revitalized with interference powders and the thread on BF Explained. Needing to know the truth, Me ordered some interference RGB powders. To prove to myself, once and for all, the RGB theory, Me mixed up just RGB powder and clear matte poly on a white matte base. Can get good gain, due to the reflective porperties of the mica flaked interference powders and good cone due to tranluscency and white base. However, was it the end all be all? No. So Me mixed up some more with some silver mica powder in order to improve blacks. It worked, but looks very similar to CGIII. Waiting for some silver interference paint to continue experiments.

Me also painted up a mirror with the RGB and flat poly mix over a matte white basecoat on the mirror. Hated it. Too much haloing. Me know Me getting off topic, but it is part of the RGB experiments Me did, but, IMO, fusion has fizzled. No fusion, looked just like the painted foamboard. Please don't take this as gospel for Me am not Him, just Me. Do your own experiments if you don't like what Me have to say. And Me don't want to start WWIII here, just an opinion and observation. Which Me is proud to say Me entitled too.

Basecoat is critical. A nice smooth, matte white base goes along way. At least, in my epxerimentation, this has been the most watchable base to use. A translucent topcoat with some gray and gain works very well. Interference colours can help get on axis gain with improved off axis gain. Dark gray, unity gain screens are really boring to Me. You are entitled to form your own decision thru discussions here and experimenting a little on your own.

In closing, Me would like to thank the academy and the AVS DIY Screen Forum for all of their dedication to this hobby. The best thing is the information learned and exchanged. Me hope it continues. However, Me is going on hiatus because Me can see the repercussions from Me honest effort, opinions and statements. Good luck to all! And remember, this is supposed to be a fun and innovative forum.

Meow.
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post #3 of 413 Old 09-05-2006, 06:27 AM
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Quote:
Originally Posted by tiddler View Post

So if I understand correctly what benven found worked was the following: A base surface of matte white, a transparent medium of flat polyurethane, and suspended in the clear poly a random dispersion of red, blue, and green reflective particles. He then added some silver metallic particles to create a gray without sacrificing reflective performance.

So anyone care to put forward a theory on what is taking place here?

Reflective mica flakes create gain. The clear poly allows the matte white basecoat to affect performance ie diffusivity. The interference powders enable the coating to stay as colourless as possible off axis improving off axis gain and performance. The silver powder I had was not interference. Therefore, off axis gain is lowered due to the grayness of the powder. The silver interference paint will help in this regard. I have not yet received my new batch of the silver interference paint to continue experimenting.

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Originally Posted by tiddler View Post

Now as far as Light Fusion goes, it sounds like benven put a matte white base coat on the mirror and then the RGB coating. I would have expected the mirror to replace the matte white base coat. I'm not sure why he did not try the RGB directly on the mirror. The density of the metallic particles would be the thing that determines the effectiveness of the light fusion. Also the thickness of the mirror is another variable that can cause problems. The mirror would ideally would be very thin. The typical mirrors we are playing with for experimenting are too thick to work properly without causing unwanted halo effect.

Just my thoughts and musings so far.

If you just put a clear poly coating on the mirror, all you would get is hotspotting. There is not enough diffusivity in the poly. Also, the translucent white basecoat helps overcome the poor off axis performance. And you are correct, in that the thickness of the mirror dsoes impact haloing. I need to repeat with a much thinner mirror. Would a first surface mirror, like a piece of mylar work here?

And, as long as these posts stay civil and do not personally attack Me, Me will continue to post and interact.

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post #4 of 413 Old 09-05-2006, 06:40 AM
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I put the following mix on a WilsonArt White Laminate.

Decoart Dazzling metallic shimmering silver
Decoart Dazzling metallic ice blue
Decoart Dazzling metallic crystal green
Decoart Dazzling metallic glorious gold
20:1:1:1 ratio

Then I added polyacrylic semi-gloss with that mix at a 4:1 ratio

Here are some picture with very little ambient light.







Here some pictures with alot of ambient light ( 80sq ft of windows and 6 can lights)





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post #5 of 413 Old 09-05-2006, 08:07 AM
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The introduction of metallic/interference RGB pigments will probably result in nice screens, but for proving the RGB concept on a more general level I'd prefer a KISS approach. Thinking about the theory, I would think that having gain is not essential for it to work.

Here's a thread that I think is pertinent to this discussion, started by prof55:
A Slightly Scientific Study of Colored Light

Now, if we look at the red filter in red light (third picture, left column, second row), we can see that it's almost as efficient at reflecting red light as the white background. And then, when we look at the red filter in ambient light (third picture, left column, first row), the difference to the white is much stronger. What does this mean? I would say it means that if we watched red-and-black movies on a red screen, it would offer improved ambient performance to a white or neutral gray screen. Because it would have the "reds" of a ~0.9 gain screen, but much darker "blacks."

Now, back in reality, where our movies, and our screens, have more color than just red, this advantage will be diminished by the inclusion of greens, blues and whites. The question is, does the advantage go away completely? Remember that all an RGB screen has to do is be more efficient than a "traditional" neutral gray screen at reflecting projector light vs. absorbing ambient to be useful.

Speculation is fun, but how to test this? Again, keeping to the KISS principle, two neutral grays should be mixed into the same flat white base. One should be a "shop color", composed of lamp black and whatever additives will make it neutral. The other mix should be tinted with RGB pigments, and made as neutral as possible. The mixes should be tinted so that in strong ambient light the RGB was very slightly darker when painted and cured. Neither should exhibit any sheen. These samples should then be moved to a light-controlled room, and shot with a PJ. If the RGB panel is brighter, then the concept works, and the RGB will offer improved contrast under ambient conditions. If it's still darker, or too close to call, well...

I've been meaning to do this test myself, but I'm unclear on exactly what pigments of red, green and blue should be used, if one wants to avoid pearlescents and such entirely. Also, using pigment powders instead of pastes might allow one to prevent one paint from developing more sheen than the other.

Quote:
Originally Posted by benven View Post

And you are correct, in that the thickness of the mirror dsoes impact haloing. I need to repeat with a much thinner mirror. Would a first surface mirror, like a piece of mylar work here?

Yes. In my experiments I've found that mylar gives you gain similar to a glass mirror, with no visible haloing.

A VERY thin second-surface mirror should also give good results, and reduce SDE in the process. It's hard to say how thin you'd have to go, but I'd guess that something in the vicinity of the width of the pixel-gap on digitals would be OK. So we're probably talking rolled goods.
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post #6 of 413 Old 09-05-2006, 08:47 AM
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The next experiment I want to try is get black laminate and apply the same mix but replace the Decoart Dazzling metallic shimmering silver with Decoart Dazzling metallic white.
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post #7 of 413 Old 09-05-2006, 10:17 AM
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Quote:
Originally Posted by rfisher1968 View Post

The next experiment I want to try is get black laminate and apply the same mix but replace the Decoart Dazzling metallic shimmering silver with Decoart Dazzling metallic white.

Nice work rfisher. If I can find the paints, I will give it a go. I have tried my mixes over a black base. Results were less than appealing to me. Please give it a try a with your mix and see what you get. However, to get better ambient light viewing properties, I firmly beleive you require a gray topcoat and not a gray or balck basecoat. Translucent topcoats that are not gray reduce the effects of deeper blacks and the screen tends to act more like white screen ie washes out more.

CoveX, some interesting thoughts there. I'm just thinking out loud; can we set up a DOE (design of experiments) with this? Is it even worth it? I may try a mix over some mylar just to see the effect. However, my thinking is that a mirror does not provide the desired "fusion" effect. I feel that the white plastic substrate pb_maxx has talked about would be a much better substrate to use. I think one requires a diffuse substrate to work with. A mirror, although it is very smooth, results in hotspotting if the paint is too thin and really no effect is the paint is too thick. If you get the paint layer just right?? will it really provide the desired results? I still don't believe that given my experiences. Matte white, diffussive bases are what I beleive is a better approach.

Meow.
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post #8 of 413 Old 09-05-2006, 11:40 AM
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Quote:
Originally Posted by benven View Post


And, as long as these posts stay civil and do not personally attack Me, Me will continue to post and interact.


I need to ask for clarification.

Who is me? By me does he mean ME or is me speaking of him.

Me or I find this thread interesting.....stick with it.

Im talking Civily and non threateningly to you.

I cried because i had no G90.... til i met a man who had only Digital.
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post #9 of 413 Old 09-05-2006, 01:04 PM
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Quote:
Originally Posted by tiddler View Post

I think "ME" is benven's inner JamaiCanadian.

No worries Mon!

Now that's funny!

So to sound like Dr. Suess...

Me is not Him
Him is not Me
Me and Him can be like Him and Me
Me like ham
Him like green eggs
But that's just Me

Meow.
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post #10 of 413 Old 09-05-2006, 01:08 PM
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Hey, rfisher, can you please put up a comparison screen next to your new mix? I think that would help me understand how well it's performing. Do you have any matte white and lite gray panels you could put in the shots? If you do can you take some on axis and off axis shots too? Pretty please with sugar on top.

Meow.
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post #11 of 413 Old 09-05-2006, 01:14 PM
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Hey Benven I think you missed your calling...
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post #12 of 413 Old 09-05-2006, 01:15 PM
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Benven, I got some BOC to compare with or would you rather see unpainted laminate compared? The big difference is in ambient light. I really don't care how it looks in the dark. Everything looks decent in the dark.
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post #13 of 413 Old 09-05-2006, 02:23 PM
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I guess that's what happens to you when you a yappy 3 year old!!

Anyway, rfisher, the laminate would be good. I assume it's white with a little gloss? A lite gray/silver panel would be a good comparison. Maybe you could mix up some of the DecoArt silver with some white paint and apply it to a small section of the laminate.

I do disagree that they look the same in the dark. Please refer to the pictures below:



Even in light controlled situations they should look different. You may have an interesting solution here. That's why I would like to see some comparisons.

Thanks.

Meow.
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post #14 of 413 Old 09-05-2006, 02:51 PM
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Benven, my mix on the laminate is a light/med grey right now. If I compare to laminate that is not painted you will easily see how much better my mix behaves in ambient light. My main goal is to create a very good ambient light screen. If it also looks good in a dark cave, so be it.
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post #15 of 413 Old 09-05-2006, 03:33 PM
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My apologies rfisher. I should have explained myself better. I don't doubt your screen look good in ambient and light controlled situations. I was merely pointing out that not all screens are like that. As you can well see from the pictures above. If your mix works that well, there may be a new one going up at my place.

By the way, where do you buy the DecoArt paints?

Meow.
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post #16 of 413 Old 09-05-2006, 04:05 PM
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I got the paint at Michaels. Its great stuff
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post #17 of 413 Old 09-05-2006, 04:43 PM
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Quote:
Originally Posted by CoveX View Post

Speculation is fun, but how to test this? Again, keeping to the KISS principle, two neutral grays should be mixed into the same flat white base. One should be a "shop color", composed of lamp black and whatever additives will make it neutral. The other mix should be tinted with RGB pigments, and made as neutral as possible. The mixes should be tinted so that in strong ambient light the RGB was very slightly darker when painted and cured. Neither should exhibit any sheen. These samples should then be moved to a light-controlled room, and shot with a PJ. If the RGB panel is brighter, then the concept works, and the RGB will offer improved contrast under ambient conditions. If it's still darker, or too close to call, well...

I've been meaning to do this test myself, but I'm unclear on exactly what pigments of red, green and blue should be used, if one wants to avoid pearlescents and such entirely. Also, using pigment powders instead of pastes might allow one to prevent one paint from developing more sheen than the other.

A valid test, but a couple of problems present themselves. Under the conditions you describe, both mixes will rely heavily on the white pigment. Even so, the RGB version should show a slight edge, since its gray qualities are produced by pigments that do reflect some colors (rgb), rather than a pigment which theoretically reflects none (lamp black). And since it is not possible to produce a true neutral gray with white and lampblack alone, other pigments would have to be added, as you say.

I propose a similar test that might even things out a bit. Suppose we make a gray using white and lamp black only, and an "identical" gray using the same white plus RGB pigments only. The RGB version will need to be a tad low on green and high on blue, since this is what you get when you mix white and lamp black. But these two colors should verify or deny the value of the RGB mix.

I have the resources to try this - I'll see what I can do, and keep you posted.

Garry
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post #18 of 413 Old 09-05-2006, 05:06 PM
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tiddler, I did roll the paint. I do have issues with roller lines but I dry rolled and it was to late to stop after I realized. I'm going to put another layer on top and fix the slight problem.
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post #19 of 413 Old 09-05-2006, 05:15 PM
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Well that answers one of my questions. The other one just for clarity rfisher, that was 4 parts of satin poly to 1 part of the coloured mix? And I assume the substrate was a Wilsonart board? Sometimes Me no read too well.

Meow.
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post #20 of 413 Old 09-05-2006, 05:20 PM
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Whoa, you're right tiddler, it was stated as semi gloss in post #6. If it is, won't it hotspot?

Meow.
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post #21 of 413 Old 09-05-2006, 05:23 PM
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I did use Polyacrylic Semi-gloss. The ratio 4:1, metallic paint mix to Polyacrylic. There is NO Hot spotting at all. The sheen is minimal and I would describe the finish as matte
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post #22 of 413 Old 09-05-2006, 05:34 PM
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Yeah, 4:1 paint to poly shouldn't hot spot.

Meow.
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post #23 of 413 Old 09-05-2006, 05:42 PM
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I used Polyacrylic Semi-Gloss because i have a canvas printing business where I use it to coat my printed canvas. But another reason is because it increases the contrast of the artwork I coat. Blacks get blacker and colors tend to get more vibrant. So I thought why not use it in my mix.
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post #24 of 413 Old 09-07-2006, 10:55 AM
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The next experiment I will do with my mix is to make a separate mix with each color component. But with the gold, I will add just a small pinch of Delta Red. They will be layered Red first, Green Second, and Blue Last(top). This will be applied on Wilsonart laminate Designer White. I will post pictures this weekend.
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post #25 of 413 Old 09-07-2006, 12:00 PM
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I used gold because Festive Red was not at the store where I bought the paint. Gold is just a replacement color.

The layering method is used because I saw good results with a earlier experiment. I also think the different wavelenths of Red, Green, and Blue make this approach allow the light to be more in-phase with each other when reflected from the screen. This method results in better performance. Just a insane guess at whats really going on.
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post #26 of 413 Old 09-07-2006, 07:00 PM
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Quote:
Originally Posted by tiddler View Post

Could you explain why you are using the gold? I would have thought the Red, Green, Blue metallic paints in a semi-transparent medium over the white substrate would be the most direct approach.

I'm also unsure what the layering is meant to achieve. If I understand the approach correctly, the idea is to have an even distribution of particles that reflect Red, Green, Blue light from the projector back to the viewer. The resulting screen should have a greyish color to it that enhance black levels. The white base provides a wide viewing cone. As far as ambient light rejection goes I'm at a loss.

I'm not questioning anything you guys are doing I'm just trying to get some understanding of what may be happening with this approach.

I'm not sure what the RGB paints do either. That's why the BF Explained thread was started. No explanation yet and we are all trying to understand. The only thing I can ascertain from my experiments and rfisher's experiments is that the paints are metallic (mica flake) and therefore reflective. Try doing what we're doing with just RGB pigments and you will not get the same results.

I think you could use any metallic paint and as long as you can balance the colour to some neutral gray/silver you'd be fine. I figure could use cyan, magenta, yellow, gold, silver, red, green, blue, purple apricot, plum, cherry, watermelon, fushia, burgundy, or whatever metallic paint. Metallics give you the gain. The bases balance the colour and the matte white base diffuses the light. That's my opinion.

Also, do we know the specific wavelengths from the projectors? How can we pick a certain hue of RGB to match up with the PJs RGB? And if we could, is it really going to make the screen that much better? Is any reflective particle good enough? Doesn't all light contain RGB? How can you filter out ambient light from PJ light with RGB particles on a piece of wood, cloth, mirror or white plastic?

To me it is pretty easy. You reflect as much light back to the viewer, with a refelctive layer, and then you have to balance that against diffusivity, for viewing cone. Many ways to skin the cat. Metallic paints/powders, reflective spheres, metallic substrates, fabrics, laminates etc. That's why we see so many of these great DIY ideas. Is one better than another? Yes, but only to the one doing the watching!!

Whew...just had to get that off Me chest Mon

By the way, weren't you gonna tell us about how you got your nickname?

Meow.
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post #27 of 413 Old 09-07-2006, 07:23 PM
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Tiddler
Hope this helps.

Red
Orange
Yellow
Green
Blue
Indigo
Violet
The colors are arranged in the order of decreasing wavelengths, with red being about 700 nanometers and violet being about 400 nm.
I think you might be onto something, artists have been using this technique for the past couple of centuries.
This,the laminate study and BFLF/deltamoon might be creeping up on the ideal substrate/ coating DIY solution so far.
Regards
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post #28 of 413 Old 09-08-2006, 05:57 AM
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I have been following the RGB idea threads for some time and not really joining in because I have been pondering all the ideas and thoughts I have seen.

Here are some of my thoughts on the concept.

First we have to assume things. (And you know what they say when you ASSUME things) assuming you have a DLP projector and as the color wheel spins around the mirror control sends little pixel size cannon balls of light to the screen. Like a paintball gun set to auto, only firing 3 colors of balls RGB in rapid-fire succession. Assuming a perfect white screen and the gun fires say 3R,7G,9B and then repeats the sequence over and over just to one pixel. We will perceive that pixel as one of several million of the colors the projector can make. We don't see it as the rapid fire of different colors but rather a constant color.

Now for the second assumption if we could know the exact wavelength of each of the 3 colors the DLP sends out we could then find 3 pigments in the matching wavelengths and blend them into a gray paint. Another assumption is that the pigments don't combine in any way but stay suspended side by side. Now why would we see them combined as gray? Because under white light they would be each reflecting back only the color they do well and our eyes will be seeing the blend of the 3 together and in much the same way we see colors combined from the DLP we see the light reflected off these tiny particles perceived as their combined color and that being gray in this case.

Now assuming the pigment particles are bunched tightly together in any given pixel on the screen roughly one third of the area would hold each color. And along came a red paintball of light and strikes the screen surfaces. What would come back to our eye? Well IMO the red light hitting the red third of the pigment would be enhanced and come back as strong red push (a good thing) the red packet of light striking the other two thirds of the pigment will be pushed by the G&B and the resulting combined effort of the 3 will cancel the strong red and the result will be right back where we started only suffering the absorbed losses equaling that of gray.

If the particles are dispersed less than total thirds into a white base or in a clear base and then applied over a white base the effect will be lessened and the apparent color of the screen will be a lighter gray, but the above will still hold true just to a lesser degree.

Assuming these pigments are of what we have been calling metallic mica's etc. and they have a color component along with acting as tiny reflective mirrors they then become gain additives. And keep in mind what Tiddlers testing showed over and over again thru the off axis shots. And that is with gain there is decreased viewing cone. (only so much light to go around) also keep in mind the reason we want the screen to look as dark of gray as we can under ambient light is to help with the illusion of blacks when projecting nothing to the screen.

So what really are my thoughts about RGB metallic pigments at this point? I think the effort should be to view these as additives to be used in conjunction with the silver metallic to correct for observed color push.

We have to set a goal for a given screen how wide a viewing angle is required how many lumens are delivered to the screen and how many foot lamberts are desired for viewing. Then if you decide that metallic is required to reach your goal you start down the many experimental paths the research is taking us now.

Are there other factors that play into this? Yes I think there are. And I think two of the biggest that help with ambient light rejection are (sheen and texture)

Like Dennis Miller always says This is just my opinion and I could be wrong.


Bud

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post #29 of 413 Old 09-08-2006, 07:20 AM
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Didn't Steve Scherrer experiment and play around with printing red, blue, and green dots tightly compacted on a piece of paper? If I remember this right he created a pattern that was very tight and pasted it over and over on the paper. It did look gray to the human eye, and it was showing some interesting characteristics when an image was displayed on it. It sounds like the same principle but different technique.

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"Make everything as simple as possible, but no simpler." - Albert Einstein
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post #30 of 413 Old 09-08-2006, 07:27 AM
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I did the same thing with my 60" printer. I made a RGB image in photoshop and then printed it on some canvas. The result was grey, but didn't notice any ambient qualities. I think the problem is the pigments CMYK = Cyan, Magenta, Yellow and Black.
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