From: Richard M. Koolish (koolish@bbn.com)
Date: 04/02/02-03:24:49 PM Z
> Good questions Katharine,
>
> When I was developing the Spectral Density method (and I certainly refer
> only to the small world of my book on digital negatives, not to the
> wider, territorial-marking world in which egos shout "I thought of this
> first!"), I wondered about the same thing: what color would best absorb
> UV? What I did was scan a piece of Masking Vinyl, the orange stuff
> printers put around negs when laying them out to burn printing plates. I
> figured that if the printing industry had decided that color was optimum
> for blocking UV, that was good enough for me.
>
> Sampling that color in Photoshop resulted in the 0/71/71/0 color and its
> newer brother 0/55/55/0.
>
> Not to say there aren't better colors...but that orange works amazingly
> well at blocking UV.
>
> Dan
>
> www.danburkholder.com
>
> You said in your message...
>
> > Which color (orange or yellow-green)
> >is closest to the exact complement of peak sensitivity?
>
Color is very misleading, especially when your eyes can't see the part of
the spectrum involved. I'm sitting here with a copy of the Kodak filter
publication B-3. If I look through the various filters for ones that block
UV to 400 nm, I find that among them are 2A (pale yellow), 8 (yellow), 21
(orange), 25 (red), 40 (light green), 45 (blue green). And most of the
blue filters block anything below 360 nm. Without measuring the effect in
the specific band of interest, it's hard to judge a filter by its color.
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