RGB Paint Mix Experiments & Discussion - Page 2

This is going to sound crazy, but has anyone ever looked at a sample of actual screen material under a microscope? Or at least a magnifying glass?

I know that won't 'unlock' the mystery of the components, but it could bring up some interesting observations. From there ideas could be tried to try and come close to what they are doing... just a thought and don't laugh too hard lol

Didn't mean to go off topic in either post... back to the regularly scheduled programing!

I have had the chance of late to look at the Da-Lite High Contrast Matte White. A friend of mine has been swearing by this stuff for a couple years and when he found out I was building a screen he told me I had to use this. When I didn't he couldn't wait to bring a sample over to show me the improvement I was missing. After less than 2 minutes he declared you have me beat with your DIY screen paint. Think is the store bought material had me by maybe .1 in gain but I had at least a good 20 degrees of viewing cone. The da-lite dropped off fast also where mine was a slow change. But the biggest difference was what Tiddler just mentioned and that's the invisibility factor. The sheen on the da-lite made the surface more noticeable. It may have looked better than mine given different ambient lighting issues. I plan on testing that some.

I did look closely at the surface and it has a texture manufactured into it and its clear there is some glossier coating over a flatter base material. Very much the way I made my screen. Its also a darker gray to start but didn't seem to help the blacks as much as it should have for the shade.

(below is da-lite info)
High Contrast Matte White
Designed for moderate output DLP and LCD projectors, this screen surface is a great choice when video images are the main source of information being projected and where ambient light is moderately controlled. With its specially designed gray base material and reflective top surface, this screen material is able to provide very good black levels without sacrificing the white level output. Screen surface can be cleaned with mild soap and water. Flame retardant and mildew resistant.

Viewing Angle: 50°
Gain: 1.1

I think he got it.


I have been posting on and off over the last month that it's all about this key word efficiency and trying to point out that gain is not the same as efficiency.

You are correct in your statement that in my case I wasn't interested in high efficiency because I had an abundance of starting lumens going into the equation. You are also right that a neutral gray no mater what goes into it is a shade of white and in being neutral it looses efficiency but still reflects the portion it doesn't absorb true to the original image colors just less of them. And the only advantage is a darker screen to give a greater perceived CR on the dark end of things.

The metallic paints I agree with all you just posted above except for the part that when put into opaque paints only the particles laying on top do any work. We know from the paint on glass experiment (and I know that paint was cut with clear poly etc) that light does travel some small amount into the paint, and I believe it travels in deep enough to contact some of the top surface metallic. But in any case most of the modern mixes have poly added and we consider these paints translucent or semi transparent. And when adding metallic to these the inner metallic is randomly oriented.

I posed the question a while back, Would there be any use for metallic paints in the case (like me) where I have excess lumens? And I answered the question with a maybe answer. I thought if by adding the metallic I could at the same time increase the efficiency and gain of the screen and in doing so produce the same bright end image from a darker gray screen I could in fact widen the distance between white and black and see improvement in CR.
I don't remember the exact set of photos Tiddler did that illustrates this but there were one or two that did. They were the ones where you did a comparison between a neutral gray poly screen and a metallic screen. I remember that in ambient they were not the same even though you tried to match gray level. Put under projector light there was a wider gap. So there can be a practical use for these even in the case of a over powered projector. But maybe less dramatic.

When I look at my screen with maybe a 150 degree viewing cone and a seating area that uses maybe the center 50 degrees, even though I'm at the high end of my foot lamberts I ponder the light going off to the sides as waste. Could I draw in my viewing cone thru gain improvements and at the same time tame some of the light thru a darker screen. Pump up the blacks and get less transmitted ambient projector light/ better blacks again.

MM started a thread where he was doing a BF screen for the same projector I have and he did the lite version of his mix. He posted something the other day that he maybe should have went with the darker mix. I think it was based around this same thought process.

Well I bought Calman yesterday and this weekend I will check the on/off contrast of my panasonic pt-ae900u on my painted laminate screen. I'm hoping for a on/off contrast of at least 4000:1

I got the Spyder Pro 2 for about $180 and the Calman Software for $100.

But contrast this situation to the red paintball hitting a black pigment. Now the red is absorbed, rather than reflected. So wouldn't a gray made from white/red/green/blue theoretically have a slight edge over a gray made from white/black?

If the idea is to use as much of the screen area as possible to reflect light, it makes sense to avoid pigments that absorb all colors.

It's probably a lot more complex than this, but this is my theory for the RGB paint. If it's strictly RGB vs black, the RGB should win.

Garry

I made a new mix with Decoart silver metallic, Polyacrylic semi-gloss, blue metallic power, red metallic powder, and Decoart green metallic. This mix slightly widened the view cone with same gain and contrast.

One mix rfisher? Or layered?

1 mix, multiple layers of the same mix.

Different colors are able to penetrate the poly differently. You are right.
Basically, for any given material, the larger or longer the wavelength of light, the more it is going to be able to penetrate. Say Red is around 630nm, Green is around 540nm and Blue is around 460nm.

If you only are using those three colors (like in a projector) then you can see that red can penetrate farther than green, and green can penetrate farther than blue. If blue was on the bottom layer of the screen it wouldn't have much chance of reflecting anything. So having red on the bottom layer, green in the middle and blue on top makes sense.

Welcome to the forums! Excellent input, this is the kind of thinking that will add much to these projects.

The peak emissions for the P22 phosphors used in CRT projectors are 626nm (red), 530nm (green) and 450nm (blue). LCD is about the same, don't have the numbers on hand. But the principle remains sound regardless of the exact numbers.

Garry

Thanks for the encouragement, I've been hesitant to chime in, even though I've been lurking about for a while.

It is my understanding that LCD pixel color filters have a relatively wide acceptance range peaking at about the same points as those in a CRT. (That's why I said "around" this many nm in my post.) Those filter ranges have been standardized industry-wide just like the CRTs. An RGB mix for screens should work well for anyone's projector if it tests well for only one projector.

I'll be adding my input here and there. Looking forward to the fun!

T.

Here's a way I think will match your projectors RGB.

Use Microsoft Paint (everybody's got Paint, right?)
Draw three rectangles.
Click the fill with color tool. (Paint bucket)
Click on the colors tab to edit colors.
Click the define custom colors button.
Click the bright red basic colors box.
Check the boxes on the bottom right of the window, they should say Red 255, Green 0, Blue 0.
Click OK.
Click the first rectangle you drew and fill it with that red.
Do the colors tab, edit colors, custom colors thing again.
Now click on the green box that is three from the left and three down.
This one should be Red 0, Green 255, Blue 0.
Click OK and fill your second rectangle with that green.
One more time for Blue - colors tab, edit colors, custom colors.
Click on the Blue that is five from the left and four down.
The boxes should say Red 0, Green 0, Blue 255.
Click ok and fill the last rectangle.
(By the way, Sat should stay at 240 and Lum at 120 for all three colors)

These are the colors you have to match in your paints.
Print that Paint file and make sure to save it, you'll need it later.
I know that it won't be absolutely exact, because you will be printing it with a CYMK printer, but it is all we have.

When you visit your Michaels or other craft and paint store get the closest match you can find. Also get the smallest container you can find to use for testing. No point in buying a lot until you know it'll work. While you are there, get a few sheets of black construction paper or equivalent and a few sheets of bright white, too.
You are going to be painting "color chips" on white squares and taping or glueing them onto the black construction paper. It'll be kind of like the color filter test that was done on the "A Slightly Scientific Study of Colored Light " thread.

Cut out four squares of white paper for each sheet of black backing paper. Leave black borders around each square. One square you leave white. The others you paint one red, one green and one blue.

Now project with your projector the Paint file you saved earlier with the red, green and blue rectangles. Stick or hang (or just hold) your "color chip" sheets on your screen, one in each color of rectangle.

Here's what we're hoping for......in the projected red rectangle the red painted square should be almost a perfect match with the red that shows on your unpainted white square. The blue painted square and the green painted square should look black.

In the projected green rectangle the painted green square should be almost a perfect match to the green that is projected onto the unpainted white square. Unfortunately, greens are difficult because they are often made with a mixture of blue and yellow pigments, and that just won't work here. It has to be a pure green pigment. If you've nailed it, congratulations and tell me what brand, color, catalog number, manufacturers part number and/or sku number it has.
Here again, the red painted and the blue painted squares should look black.

Do the same again with the Blue projected rectangle.

Even if they aren't perfect matches, if you are happy with the color intensity and brightness of the color squares, go for it.

If you are not happy with the results of the samples you've tried, well, it's back to the store (and probably looking at the more expensive artists colors, dammit.)

If you go with the metallic paints, let us know how they turn out. It would be great if they intensify or brighten the color without sacrificing too much viewing cone.

If you have to use Artists Acrylics, I suggest starting with Cadmium Red Medium, Cobalt Green Light and Cobalt Blue. (Hopefully pure pigments).


T.

Thanks Tgreenwood. Latetly, lotsa great thinking coming from these forums.

Anyway, I am a little confused as to what we are going to accomplish here with RGB. What do we predict will be the outcome if we use the "correct" RGB paints on a substrate? Should we be layering the paints? If we do, all we will end with is, primarily, the last colour being reflected. I have done this, even with translucent paints and the results are not very good. If we mix the RGB paints together, what go we get? I have done it and you really never end up with a neutral gray without adding more paint/pigment. Even if we get it just right, not very easy for DIY, all we will end up with is, at best, a unity gain gray screen. Yes, it will preform a bit better in ambient light because it is gray. But is that what we want here??

Do we want an a screen we can view with some ambient light? Or, do we want a good all around performer?

I firmly believe we require metallics in these mixes. Without them, IMO, the screens are drab and boring to look at. Just my 2 cents.

Don't be confused because Me confused Mon! Let me start off by saying, I have not seen one shread of evidence to prove that the RGB method is a better method than any other approach. Until I see that evidence, I am a non-believer in an RGB method. This is based on my own testing of 3 or 4 variants of the BF mixes.

Now, we get back to the pigment vs metallic thing. Let me simply make this analogy. If you had 2 samples, let's say both the same "colour" of blue. One was just a pigmented paint and the other a "metallic" paint. Which would look "better" when being projected upon? In general terms, we can say that the metallic blue would be more reflective than the pigmented blue. Also, the metallic blue would be less reflective off axis than the pgimented blue. So... back to my original question, what are we trying to accomplish? Reflect more of the projected light back to the viewer degrading cone or reflecting less light back to the viewer and increasing cone? Like you stated, it depends on your own personal situation. Me, I like gain. Somebody else may be happy with a less than unity gray screen.

Lotsa different ways to skin this cat. RGB pigments, still, IMO, just balance the colour of the mix. Period. It does not reflect more RGB light back to the viewer. Maybe I'm wrong but this has not been proven to the masses. Even though we were specifically asked to start a thread on the subject BF Explained. I will eat my words if someone can prove to me that RGB pigments are the way to go.

Colored metallic paints are usually composed of a transparent base, pigments, and either mica or aluminum flakes. The pigment is the only real source of the color - the mica or aluminum is for sparkle only, though it may contribute a wanted or unwanted color when used in a screen. And not always the same color, either - since they can act like tiny prisms, the color can depend on viewing angle. In suspension, this would usually average out to a single color, but that color can vary quite a bit with film thickness, since it is dependent on the orientation of the shiny bits.

A good example would be some of the very fine metallic automotive paints. A light blue of this type can range from blue to silver-gray, depending on film thickness, surface texture, and viewing angle. It all depends on how the paint is applied.

Interference paint is another story. It is composed of a transparent base, and mica flakes which are coated with titanium dioxide (white) to a specific thickness. This changes their refractive index so that they reflect a specific color, but this color can also vary depending on application technique.

Another word about metallics: The mica or aluminum flakes can vary in size and shape. They can be nearly identical (in a top quality paint), or there can be many different sizes and shapes (in a cheap craft paint). This will affect the performance of the paint, particularly the color. And since craft paints don't really have to match anything, they will vary from batch to batch.

I agree with Ben - metallics can give much better performance than pigments, especially where higher gain is desired. But they are much more difficult to control than pigments, in terms of both gain and color. When spraying metallics, it is possible to paint a screen that has accurate color on-axis, and pushes badly off-axis. Film thickness measurements would be mandatory if a high metallic mix were to be exactly reproduced.

In my opinion, metallic-based and pigment-based paints each call for a different DIY approach. Metallics offer the best performance potential, but "pigment only" mixes are much easier to reproduce.

Garry

Premixed metallics are both pigmented and metallic, but they would have to be considered metallics for this discussion. Using them is a minefield, really. It would be better to add mica as a seperate ingredient, rather than relying on the unknown quantity and quality that is in these craft paints.

As far as which brands, Liquitex is the most consistent (but expensive). All the hobby paints can vary in tint and metallic content, plus they use cheap pigments that may fade.

Insect parts do have a place in the coatings industry, but shellac has not been used yet in any screen paints that I am aware of. On a similar note, I have inadvertently added cat hair to several mixes, and it has no positive effect.

Garry

Wet Film Thickness Gauge

This is well within the reach of any casual roller or spray painter. It is a small brass or aluminium (aluminum for the cousins in the States) tool that wouldn't cost more than a couple of bucks.
It's dead easy to learn to use and if we ever hope to reproduce any coating on any substrate it's a tool that one should be familiar with.
They would be available at any large paint distributers , industrial paint reps give them away to guys on sites ,a search through a local phone book would turn them up.
The problem though is finding out what specification of wet film thickness you want to achieve for each type of paint and substrate.
I raised this once before on another thread and got hammered for it. There are only one or two people around these sites who would know what the ideal film thickness for their paint formula would be and if they worked by feel then it's more like art and very hard to reproduce.
I must be pretty slow ,I've just worked out why I got hammered for asking about this before, the phrase "best applied under factory conditions" says it nicely.
There would be a lot of R & D go into getting it just right so it might be outside our range, a couple of microns too thick on a mirror or piece of formica and you might as well have painted cardboard.

I've got a RS Maxx Mud painted canvas screen at the moment that I love ( although I loved the Artic Grey ceiling paint screen before it) and I've been waiting for about six months to get some info before I go again , First I waited for the shoot out that didn't happen , the poor guy that was doing it got sick, then I've waited for the BFLF mix to be updated and thats understandable now that it is properly commercialized. So I'm really happy that the new threads are opening up some exciting possibilities backed up by some objective data and sound thinking . I'm now glad I didn't do my usual and rush right in.

"Right discussion leads to right thinking which leads to right action"
Regards Gary

I remember that thread and post transdog. Too bad you got hammered. Do you have any details on the device? Where we could buy one? How they work? Please and thanks.

And, I guess I need to do a better job expressingmy thoughts. Prof is right as usual in his ascertation. I should have specified metallic powders and not paints in my posts above.

Also tiddler, I don't think anyone else is using or experimenting, at least I haven't seen any posts on, with metallic powders. Let alone interference powders/paints. Although brucecan was the first, that I had seen, to mention interference paints.

Tiddler it's interesting that you pointed out that the basic RS-MaxxMudd metallic mix is still your fav. I was actually waiting for the BF final. I see that is futile now, but this has allowed me the time to think about what I want out of a screen and why I would want a grey, RBG=grey, based screen.

Reason 1.
As most are aware, projected black tends towards grey, so we use a grey to shift the reflected light. Remember this shifts all light(colours).

Reason 2.
Ambiant light, from what ever source. A basic Lamp Black grey can achieve good results.

I use currently Dulux Thomas Tallis 474 with contains a small amount of black oxide.

I can control 95% of my viewing ambiant light since I mostly watch movies only at night, reason 2 isn't really a good enough reason.
But reason 1 is for me.
Now this leads me back to the basic metallic mix which has by your testing and results has improved punch, and more importantly opened up the contrast by a small amount. Deepened blacks with little shift in white.

So LB Grey and RBG made grey may work, but I feel there is to many varibles for a one for all mix.
The reason I am not happy with my current screen is the colour shifts.

The variables can start with "your projector" itself and it gets worse from there.
Actually I feel that the manufacturers may by chance actually know more than us about projectors and the resulting reflected image and so we would be best to try to limit colour shifts caused by the screen we could make.

I'm actually going to drop the gold out of the RS-MaxxMudd mix because my aim is to get closer to a true 16 black, with the least colour shifts. If I want the warming nature of the amber I will use a filter where I can tune by using different grades any time after producing the screen.

The tuning leads me back to RBG or lamb black, black oxide. I'm not convinced that there is a cost effective DIY RBG mix that suits all. Because of all the variables for any one person's setup. You could waste alot of time and money painting 10 screens to get the perfect mix. The incremental nature of this, you might as well pay for someone elses research and pay for their product as it will be cheaper.
The punters of DIY will flame me for saying that, but I feel the basic grey created from a black into white produces an effective screen for ambiant light and deepened blacks for the loss of a colour shift. The net result though is a cost effective DIY screen.

Thanks for bringing this up again Gary, I think it's a fine idea. I recall the thread, and was also a target - we were interrupting someones hype...

Here's an example of a wet film thickness gauge - only $12.00:

http://www.farwestcorrosion.com/ccpc...s/gardco01.htm

There are also disposable ones available from BYK Gardner for about 50¢ each when bought in lots of 50. I have their catalog, but they don't seem to have online ordering. If there's enough interest, I'll order some.

Garry

Most Industrial paint supply stores usually hand these out to their customers for free.

The guage pictured here is from M.L. Campbell paints, I have used this one before to measure film thickness of some lacquer I sprayed. Most manufacturers specify a maximum dry film thickness for catalyzed paints, if you know the solids by volume content of the paint, you can can calculate dry film thickness from wet film thickness.

When I read the different posts in this forum, it seems like the most difficult concept to accept is that a projector (or an LCD monitor or a CRT) puts out ONLY Red, Green or Blue light. No other colors. It is the combinations of red, green and blue at different intensities that make us percieve other colors. The computer monitor you are looking at now only has red, green and blue pixels.There are no yellow pixels, no brown pixels, no orange pixels.

I've found that a good tool to explore that concept is plain old microsoft paint. Just open ms paint and click on the colors tab, edit colors and click on the define custom colors button. Mess around in that little color space and you will find that a nice bright yellow is made with equal parts of red and green pixels. Brown is also made from red and green pixels, but there are twice as many red pixels as there are green. The range including White-Gray-Black is made with red, green and blue pixels in equal parts. Play with MS Paint and you will see what I mean.

I think what we are looking for here is the most efficient way to reflect those red, green and blue pixels off of the screen, so we are trying to use RGB pigments. Understand that RGB pigments do not reflect "more" RGB light back to the viewer as compared to a pure white screen. RGB Pigments do keep non-RGB light from being reflected back to the viewer. If the wavelength of light hitting the screen isn't in the wavelength range of one of the RGB pigments, it will be absorbed, not reflected. (I don't like the term "ambient light rejecting" I prefer ambient light absorbing".)

Here's how I look at it. Here's the spectrum of sunlight, plain old white light from the sun.
(No URLs or image calls until I have five posts, so please see attachments......)
See attachment sunSpectrum.jpg

The intensity of each wavelength is pretty much constant across the visible spectrum.

Lets say that the combination of your projector lamp (they produce a spectrum too) and the pixel color filters let through Blue light from 440nm to 460nm, Green light from 515nm to 535nm and Red light from 625nm to 645 nm or thereabouts.

If you have matched up your projectors RGB with red green and blue pigments in your screen, all other wavelengths will be absorbed, OK? Lets see what that does to the spectrum of light from sunlight.

Another image for you....
see attachment projectorrgbspectrumchop.jpg

It looks to me that ambient light washout should be reduced by a good 80 percent since the screen is now only reflecting 20 percent of the ambient light - the ambient light wavelengths that fit into those three sections of color that the screen is reflecting. The colors reflected off of the screen should improve just as much, because the black levels should improve that same amount. Contrast is everything.

Of course, all this won't mean diddly unless we can find pigments that will reflect the projector's RGB well enough, like I outlined in my previous post. Thankfully, the color filters in LCDs in projectors are pretty similar. If we work together, chances are that we can find pigments that will work for everyone.

Once we find the correct pigments, it's off to the races! Then I can see all kinds of experiments with mica flakes and all other sorts of paint mediums and blends and reflective ingredients and substrates and etcetera, etcetera.

T.

Thanks T for your input. I, for one am all for learning so please do not take this the wrong way. I am just asking some questions and want further insight.

First off, I guess one thing we also forget about... is that some DLP PJs have other colour segments on their wheel. Say like yellow and white. Wouldn't this change the projected spectra from what you have presented?Doesn't this blow up the entire RGB theory?

OK. Now, I can buy the theory you stated above T for PJs with only RGB panels or wheels in sunlight. However, in recent weeks, I just made up a few mixes with nothing but RGB interference powders. Are they the correct wavelength? I don't know. I will need to play around with paint and my PJ to see if this is true or not. In any case, this mix was no better than any other mix I had lying around. As a matter of fact unless you added some silver powder to it, it would wash out in ambient light. Maybe it had to do wih the fact that the powders were interference? On axis they are RGB, so it shouldn't matter.

What about lighting inside the theater? There are many types of light bulbs out there and they all have different spectra.

This little experiment proves to me, that the RGB method, while sound in theory, is not very practical. And I am left wondering why??

Any gray screen will look better than any white screen in ambient light viewing conditions. What makes the RGB method any better? I would need to see some real life mixes side by each to make my conclusion on which method is better.

Having taken a few days off from the forum and coming back to this thread I had a lot of catching up to do. I'll start with prof55's reply to mine.

See post 55
In both cases we are talking about paint that is color neutral and gray to the eye under low lighting levels. And in my mind the way a gray screen works is it reflects the total spectrum of light back when projected to. So in essence it is white or a darker shade of white. That's why under bright projected white light we don't see a bright gray screen we see white because white light is the reflecting of the total spectrum and that's what's coming back the total spectrum, just that some of the light is being absorbed into the screen. Under low light level projecting the projector competes with ambient light to a greater degree. At these times the gray absorbs some of the ambient a good thing along with some of the projected a bad thing. But we have control over the projected and we just send that amount more to make up for that.

Now if we make two screens one with a large component of white and a very small component of black say 22/48 oz. / gallon. And then a second paint that is mixed to have the same outward appearance using a large part white and I would assume a total RGB pigment of something like 22/48 oz / gallon total. (and I know that's not the correct amounts but I'm speaking analogously.) In both cases we are maybe 95% of the projected light reflecting off of white pigment and 5% off the stuff making it gray. So in the case of the lamp black we are just loosing that 5% and in the case of the RGB pigments we are accomplishing the same gray and in doing so we are enhancing 1/3 of that 5% while color shifting the other 2/3 of that 5%.

So there could be some merit to doing this still but in the ranges of grays I think are needed to get the ambient light benefits. The resulting improvements weighed against the problems with finding these true RGB pigments is a wash. Keep in mind like we know lamp black in itself wont produce a neutral gray if any of these craft paint pigments don't fall right on the spectrum the projector is shooting out we will get likewise color shifts.

Just some quick thoughts here on a Monday morning.

Try making gray with RGB paints. Not that easy. With pigments, it is much easier. You're correct on the RGB powders, they make more of a pearl coloured mixture in a clear base.



Why?? I want to keep examining this whole BF thing. If there is somehting to it, we shouldn't just keep on the powder route. Nobody has really experimented with powders other than myself. I don't want to lead people down the wrong path. Let's keep our discussions open to whatever methods we think best. If it's powders, and someone else will have to try them out, so be it. If it's pigments so be it. I think we all want to learn and eventually have the best screen possible!!

looking for Green metallic powder. I got Blue, Red, and Yellow, but no Green.

I'm also still wanting the reflectivity of Decoart Metallic silver or white, RGB metallic powder and polyacrylic. I noticed that the Folkart metallic paint had some hot spotting problems.

Also looking at a spray can solution, which will take me away from an RGB solution.

On ambient light:

This could be seen as off topic but actually the discussion of ambient light is on topic in every DIY paint thread because without it we would all be enjoying some pretty simple white screens I think.

It was brought up above that the term ambient light rejecting is not the right term and it should be ambient light absorbing. I believe that statement in part.

So far I have found 3 ways ambient light can be dealt with. In the case of the neutral gray screen it's in the mode of absorption. That's number one.
Number two has to deal with screen sheen projected light comes from a fixed point and is returned to us in a viewing cone shaped pattern. Projected light coming into the screen at a fairly straight angle can pass thru the sheen and return to us fine if the sheen is kept to a level that hot spotting isn't a issue. Light coming from above and the sides striking the sheen at a slight angle, has the opportunity to glance off the surface and not interfere with what we see. The lights pass thru each other, this method I would call rejecting. The third method of dealing with ambient I have found is texture, I'm still not sure how texture works in doing this I have thought a great deal about it though. And I do know commercial screens employ directional texture. And I have seen in my own testing with random texture with same paint mixes I have better side by side rejection over texture.

I left Gain out because it defeats ambient light in a different manner it works by making what we see brighter thus the ambient is proportionally less. Gain gives the appearance of great ambient light qualities when viewing brightly colored bright images such as sports.
Screen efficiency could also be seen as ambient combating in these situations.

OK. Why don't we change the title of this thread. It may make it more clear. I thought this for for all RGB solutions, paints, powders, pigments. It's your call.

White (Clear, actually) on the color wheel presents no problem since the red, green and blue on the rgb screen will reflect equally making white coming from the screen. Yellow is another story. If you have a DLP projector that has yellow on its color wheel, you either have to depend on the white from the base paint that the rgb is mixed into to reflect it back, or add a little yellow to the mix. Yellow doesn't take up much space on the spectrum, so it shouldn't effect efficiency that much.


The only way to find out if RGB interference powders reflect the wavelengths your projector puts out is to test it. I don't know enough about interference powders and how they work to venture an opinion.


I don't think that there are many lightbulbs out there that would put out just the red, green and blue and wash out the rgb on your screen. I've attached a couple of spectrums of a couple of lamps to illustrate that most of the light from them would be absorbed by the RGB in the screen.


RGB is the theory behind how Chromaview screens work. It'd be great to get a little taste of that great black level in a DIY screen.

No matter what kind of RGB you want to use on your screen, pigments, powders, metallics, interference powders or mashed centipedes, the RGB you use has to be matched to the RGB a projector emits or it doesn't help at all. If they are matched, the whites stay white and blacks are much improved.

T.