Even more on lenses and optics....

After some discussions on irc with some knowledgeable people in #dlp3dprinting

There is no need to modify a working projector. Make sure you have a projector with 3k lumens or more and you can either use a mirror ala this instructable  or with closeup lenses from cameras. The b9 creator I think it was is using a +4 closeup lens for their unmodified projector.  77mm lens packs with 6 assorted lenses can be had for 12$

At this point if I want a better DLP I dont need to worry about destroying a projector I can just use a good one and when not printing I can watch tv :) although i seriously doubt I would waste valuable bulb life on a movie.

I know my eyes are particularly sensitive to uv, its both inherited and sensitized from years of contacts and a little laser surgery. Because of that I've been waiting on some glasses but I'm not the only pair of eyes wandering around and while I have been making sure kitty is out of the room when I fire up the UV I thought I should take a look at case options for containing the near UV I'm working with. A little looking on line and I see tap plastics acrylics block a decent % of UV so I wandered down with a 405 nm light source and something fluorescent I found the amber worked well.

bare 405nm 9 bulb flashlight pointed at paper with highlighter

camera behind filter light source in front of filter

This picture shows that fluorescence is a re-emitted light its visible through the near UV filter

Light through filter, camera unfilterd

camera and flashlight behind lens, the brighter spots are reflections from the shiny surface

Here you can see that light has made it through but unlike the pic 2 above there is no fluorescence thus the light penetrating the filter is no longer 405