This method of building your own projection screen is new to us. [Sean Michael Ragan] ran across some sand blasting material made up of minuscule glass beads at Harbor Freight and inspiration struck. He purchased a fifty-pound bag and set out to see if it could be used with regular latex paint to create a projection screen. The answer is an absolute yes, but results are dependent on how you apply it.
Now there is paint you can buy which will turn your wall into a projector screen, but it’s expensive. [Sean’s] hack isn’t a direct replacement as he found the results of just mixing the beads with paint and applying them to a vertical surface weren’t up to the standards he’s looking for. But if you build a screen to hang on the wall you can let gravity work for you. He laid the screen flat and applied a heavy coat of paint to the surface. He then sprinkled a heavy coat of the glass bead over the wet paint and let it dry. Finally he cleaned off the material which didn’t stick and hung it on the wall.
Don’t have a projector to use with this hack? No problem, just build your own.
[Thanks Skuhl]
Nice. I also love the cat…
Sooooo 2011 i’ve see it last year on make blog, but nice to see it again. Very cool project, i’ve thinking since last year if it will work it if it will work, when i cover a aluminumfoil with a matte screen to hook up the reflexion.
So we have hipster hackers now?
Hmm. I don’t 100% get the point. Why use something else then just a really white wall? All the commercial high gain screens have the tendency to work only for a set of viewing angles. If you don’t sit directly in front of it, brightness drops towards the edges. Which makes perfectly sense- a really white wall is as perfect a lambert radiator as it gets.
Mostly because a white screen washes out any shadows or dark colors if there is any ambient light.
A light grey screen with glass or metal dust added for reflection allows for you get get brighter colors without this washed out effect.
Also, in a dark room you get better color accuracy this way ( once the projector is calibrated properly)
It’s also worth reminding the guy who tested different paint methods to improve the projection surface:
aaand with fixed html tags: DIY projector paint test results
There are a few threads on the AV Science Forum that discuss this…
http://www.avsforum.com/avs-vb/
And he can use the leftover glass beads for kitty litter!
Apparently, setup requires a cat.
yeaaaaah – good for me (:
Sift the beads first to get rid of the dust. Also: wear a dust mask and goggles.
Or just use some paint and some patience.
this has me wondering:
would it be possible to get reflective beads that are the right color of red, green and blue, so as to give off the best reflectivity of light from the projector, and attempt to minimise reflected light from other sources (window, lamp, etc..)?
[] you understoodadditive/subtractive color mixing.
One test I’ve never seen is this:
* First paint white
* Then mix (acrylic) binder medium with the glass
* Apply the mix
Binder mediums will dry transparent. So you will have a coating with the glass in it, not attached to it.
Using glass beads means it’s not sandblasting anymore btw :) glass beads!=sand
Yes Mr Pedantic, but it is commonly referred to sand blasting regardless of what the blasting media is.
My Screen is a painted wall, but not white! Plain white is bad for color depth an poorly renders the blacks. The best bang for the buck :
Behr paint, color : silverscreen. Just gray enough to give the right color depth aud blacks. I also mixed some glass microballs into the paint (the one used with epoxy for fairing compound in boats).
I tried using glass beads for a screen in 1997 or so, because I had gotten a cheap deal on a surplus CRT projector (Electrohome ECP) which wasn’t really bright enough, so I figured I could really use the gain. It was actually an original idea of mine, after I saw how the city used glass beads to make crosswalk stripes and such more reflective. I just used a paint roller to paint the wall and a sandblasting wand with an air compressor to get the beads on. But the result was somewhat streaky because the paint dried too fast. I found that I could not paint the whole wall at once because of that, so was painting a strip with the roller, blasting it, painting the next strip and so on. Thus the streaks. A slower-drying paint would help, but I just put up with what I got instead. Later I was thinking of giving up on the high gain (projectors are bright enough now) and trying to mount some electrostatic speakers with a framed cloth screen in front. Didn’t get around to that, and now we have moved. Still own the house though, so I might still get around to it eventually if we move back.
Good job and a great idea! The only caveat that I see is that this type of screen will only work well for a projector sitting on a table in line with the viewers and not hung from the ceiling. There are basically two types of screens, reflective and retroreflective. A screen with glass beads is retroreflective (the light is reflected back along the projected axis). The rule is to use a retroreflective screen if the projector is going to be on the same side of normal (an imaginary line perpendicular to the screen) as your audience. Use a reflective screen if the projector will be on the opposite side of normal from your audience; i.e. hung from the ceiling.
Good idea, Not sure if I would be messign with the paint and the media though, Maybe if I could spray the latex.