From: Sandy King (sanking@CLEMSON.EDU)
Date: 09/25/01-05:55:52 AM Z
Most common plate glass cuts off UV radiations below 300nm. However,
I think there would be little to be gained by removing the safety
glass, apart from the safety considerations. Although dichromate
colloids are quite sensitive to radiation in the 200-300 nm region
this light gives image of very low contrast. You could verify this by
testing a step wedge with one of your exposure units, with and
without the plate glass.
Sandy King
>In dichromate processes, and perhaps some others, the greatest exposure
>effect appears to be in the range of 200-310nm. Unfortunately, these UV
>frequencies are quite dangerous to us humans, and so are usually limited by
>the manufacturer, who places a piece of plate glass between the UV source
>and the outside world.
> I have, for example, two exposure units here: a Theimer Violux and an
>Olec AI-15. Both are capable of producing exposures in this range, but only
>if the safety glass is removed.
> If one wishes to test the utility of quartz glass, one must first make
>sure that their light source produces light in the range usually blocked by
>fused quartz....
> Just a short comment - Ed
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