Alright, I'm looking into building my own exposure unit. I've got the basic design I think I'm gonna go with down in my mind, but I've got a few questions.
I'm planning to do a vacuum frame. I'm not really sure what material to use for it though. I was thinking maybe the stuff they use to line ponds. I'm not sure, but I think that stuff has a bit of elasticity to it. What are some of the popular materials used?
How think should the glass be? Are there problems with it being too thin(other than easier breakage)? Are there problems if it is too thick?
Which is better, metal halide or mercury vapor? I've heard both are good, but am not sure which to go with. Also, how far away should I plan on making the light source(though I may end up making it adjustable anyway)?
Is there any benefit in having the light from above vs below vs horizontal? My initial thought is that it wouldn't have any effect, but I figured I might as well ask. The only thing I can think of is that horizontal may take up more space.
I think that's all the questions I had for now. Thanks for your help!
Questions about building an exposure unit 
