I have been looking at others projector projects to get ideas for mine.
What I have knoticed was everyone is painting the inside of there projectors black. But Black absorbs all the colors, giving it that dark color known as black. Also because it aborbs all the color it is the hottest color.
Why not paint the inside of a projector white. White reflects all the colors. So wouldn't it help the projector to paint the inside white?
Full Version: Inside Projector color.
QUOTE (Xeniczone @ Jul 8 2008, 02:55 AM) 
I have been looking at others projector projects to get ideas for mine.
What I have knoticed was everyone is painting the inside of there projectors black. But Black absorbs all the colors, giving it that dark color known as black. Also because it aborbs all the color it is the hottest color.
Why not paint the inside of a projector white. White reflects all the colors. So wouldn't it help the projector to paint the inside white?
What I have knoticed was everyone is painting the inside of there projectors black. But Black absorbs all the colors, giving it that dark color known as black. Also because it aborbs all the color it is the hottest color.
Why not paint the inside of a projector white. White reflects all the colors. So wouldn't it help the projector to paint the inside white?
White color reflects lights and keep the case cool. However, the light reflected from the case interferes with light from the lamp. It's interference light when you snap a picture and the Sun gets in the way. It makes your picture less sharp and washed out. That's the theory. I saw people putting aluminum reflection all over places without caring about the path of light, and their pictures appear to be Ok. Strange indeed.
QUOTE (Nan Null @ Jul 8 2008, 12:18 AM)
White color reflects lights and keep the case cool. However, the light reflected from the case interferes with light from the lamp. It's interference light when you snap a picture and the Sun gets in the way. It makes your picture less sharp and washed out. That's the theory.
Correct.
To quote SupraGuy:
QUOTE (SupraGuy @ Jun 21 2007, 06:01 PM)
Here's another consideration to think about.
Say that you make the whole inside mirror polished aluminium. All of that heat from the lamp has to go SOMEWHERE. The lamp dissipates the heat, both physically and as IR radiation. It has to go SOMEWHERE, and IR won't heat air. If it doesn't heat the walls of the projector, what's left? Well... Wires, fresnels, but mostly, your LCD. The LCD converts 90-95% of ALL the light that hits it into heat. Any light or IR that gets turned to heat somewhere else does NOT get turned to heat by your LCD. Therefore, as far as I'm concerned, all of the light (Other than what I want for a projection) that I can keep from hitting is a good thing.
Painted MDF is more scorch resistant, regardless of the colour or heat tolerance of the paint itself. This is because MDF is really just packed sawdust. It's even permeable to air when unpainted. Paint seals the stuff together which makes it impermable and as a side effect, increases its resistance to scorching, and ultimately catching fire. Therefore, with MDF at least, painted is less likely to catch fire than unpainted, so long as the paint is thick enough to seal. (Personally, I recommend that you use a primer coat for this reason.)
Commercial units don't need it as much for a few reasons. First they usually use lower wattage lamps. Second, they have specialised cooling, third, they have more completely sealed lamp chambers. Somewhere in there you can also add the more specialised short arc lamps for more precise delivery of light, which prevents off-axis light from even existing.
Say that you make the whole inside mirror polished aluminium. All of that heat from the lamp has to go SOMEWHERE. The lamp dissipates the heat, both physically and as IR radiation. It has to go SOMEWHERE, and IR won't heat air. If it doesn't heat the walls of the projector, what's left? Well... Wires, fresnels, but mostly, your LCD. The LCD converts 90-95% of ALL the light that hits it into heat. Any light or IR that gets turned to heat somewhere else does NOT get turned to heat by your LCD. Therefore, as far as I'm concerned, all of the light (Other than what I want for a projection) that I can keep from hitting is a good thing.
Painted MDF is more scorch resistant, regardless of the colour or heat tolerance of the paint itself. This is because MDF is really just packed sawdust. It's even permeable to air when unpainted. Paint seals the stuff together which makes it impermable and as a side effect, increases its resistance to scorching, and ultimately catching fire. Therefore, with MDF at least, painted is less likely to catch fire than unpainted, so long as the paint is thick enough to seal. (Personally, I recommend that you use a primer coat for this reason.)
Commercial units don't need it as much for a few reasons. First they usually use lower wattage lamps. Second, they have specialised cooling, third, they have more completely sealed lamp chambers. Somewhere in there you can also add the more specialised short arc lamps for more precise delivery of light, which prevents off-axis light from even existing.
Read the rest of the thread: Black Paint Inside Unit, Is It Needed?
Thanks that is a good point.
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