Projection screen colour?

Spectralis wrote on 7/29/2015, 9:39 AM

I'm sure some of you have a lot of experience projecting video. I'm setting up a show where I need to project onto a wall. The room will be in almost total darkness so light is not an issue. The wall is currently painted white but I've been told that a light grey will bring out greater contrast. Is this still necessary with modern HD projectors that have a lumen output >3000?

I'm also wondering about whether to use specialised projector paint on the area where the film is projected. And using a non-reflective black boarder around the projected image. Will any of this significantly enhance the image or is this unnecessary?

Comments

malowz wrote on 7/29/2015, 5:20 PM

light grey will bring contrast????

AFAIK, nothing will enhance projector contrast, painting darker tones will only darken the image. this will reduce the black level and also the white level, so, the contrast remain the same.

a mate white i believe would be the best option. a more glossy paint i believe will give a "shinny" look, so i would avoid that.

total darkness is very good, the darker, the "stronger" the projector light will look.

don't need to put a border around the image, unless your projector is not in the same aspect as the image (like a 4:3 or 16:10 projector) so you can "hide" those dim black bars it will create.

if the projection looks OK for the size of your projection, then it's fine. if is too dim, you can get a projection screen with "gain" and fix on the wall to get a brighter image.

Chienworks wrote on 7/29/2015, 6:02 PM

Completely agree. Anything other than white will just make the image darker. The only thing that affects contrast is ambient light; the less the better.

My high school has a humongous shiny glossy sheet for a screen in the auditorium. I don't know why it was considered a projection screen by the manufacturers. No matter where you are in the auditorium there's a spot on the screen that looks like someone is shining a flashlight back in your eyes. Matte is far superior in any case where the projector is brighter than a candle.

However, i wouldn't worry about it too much. Whatever color the wall is painted, as long as it's not too saturated or dark, the audience's eyes will correct for it after a few moments and they won't even notice that it's not white.

musicvid10 wrote on 7/29/2015, 6:40 PM

Ordinary matte Superwhite is what theatres use on back walls for projection. Works fine. It's the "wash" from other lighting that creates problems.

ushere wrote on 7/29/2015, 8:09 PM

projecting onto matte white wall at moment. no problems, just wondering:

any thoughts on the older style 'bead' screens, still have one rolled up somewhere?

Spectralis wrote on 7/29/2015, 9:10 PM

Thanks for your replies. I was referring to what is know as "digital grey" by GOO and some other screen paint manufacturers. Apparently using a very light grey is supposed to make blacks blacker even though it slightly affects the whites adversely to give greater contrast but I think this idea was used when projectors had much lower lumen levels than they do now. I just wondered if it was still applicable. I'm very pleased that I can keep the wall white and not have to fiddle about with screen paints. Having said that, using black paint to disguise black banding either side of the image is potentially a very useful idea.

Red Prince wrote on 7/29/2015, 9:25 PM

Technically, white is just light gray and black is just dark gray. That is because no matter how white you go, you can always go whiter. And no matter how black you go, you can always go blacker. I mean, pure black only exists in theory, no real-life material is absolutely black (a material that reflects no light at all). Similarly, no real-life material is absolutely white (a material that reflects all light).

It’s all relative. Our brains are well adapted to that, so they adjust and will consider the brightest material white and the darkest black.

For best results, you can help the brain by projecting on the whitest material you can get in a room as dark as you can get with a projector with the strongest light bulb you can get.

Chienworks wrote on 7/30/2015, 7:10 AM

No, the wall color cannot create greater contrast. Also, the dimmer the projector, the lighter the wall should be. A low lumen projector already has darker blacks" than a brighter projector. So, their advice seems to be backward.

Now, if you have a very old projector with a very low contrast range so that the "blacks" still pass through a lot of light, a darker wall may help mask that. However, such a projector is going to have a pretty poor image and the darker wall is going to make the entire image darker, but it won't improve the contrast at all. And, this is true of a low contrast projector no matter how many lumens it has.

farss wrote on 7/30/2015, 7:17 AM

[I]" Having said that, using black paint to disguise black banding either side of the image is potentially a very useful idea. "[I]

Use a matte black tape for that. Anyone that sells gaffe tape should have it.

Bob.

bill-kranz wrote on 7/30/2015, 8:02 AM

Benjamin Moore makes a paint called
"Super White"
PM-1
A brilliant, almost sparkling white, this clean shade suggests clarity and simplicity.

FYI

John222 wrote on 7/30/2015, 11:10 AM

I would suggest you go here...

http://www.avsforum.com/forum/23-screens/

Matte white is the most popular. Btw if you can, paint the other walls and ceiling a darker flat color. In bright scenes the screen will reflect the light to your walls and ceiling and back onto the screen. Not a good thing.

rmack350 wrote on 7/31/2015, 7:04 PM

any thoughts on the older style 'bead' screens, still have one rolled up somewhere?

Are those old style? It's a glass bead screen. Normally they're brighter in a narrower area directly in front of the screen. They have less falloff to the sides, spilling less light on the sidewalls of the theater and delivering a brighter picture to the seats. Usually an old one rolled up somewhere has some major spotting on it and is a disappointment when unrolled.

This page mentions gray screens: https://en.wikipedia.org/wiki/Silver_screen#Other_screen_types

ushere wrote on 7/31/2015, 9:04 PM

thanks rmack350...

i might just see if it actually unrolls first ;-) it was bought by a client for a presentation about 15 years ago. he stored it rolled up for about 8 years, did a clean out and i ended up with it, still rolled up...