From: Halvor (halvorb@mac.com)
Date: 04/09/03-11:21:49 PM Z
on 10-04-03 13:39, Ryuji Suzuki at rs@silvergrain.org wrote:
> From: Halvor <halvorb@mac.com>
> Subject: UV Enlarger
> Date: Thu, 10 Apr 2003 13:26:44 +0900
>
>> I have been digging around in the archives a bit and have seen that
>> this subject, an UV enlarger for alt print. have been discussed
>> several times, I just wondered was there ever a conclusion to this ?
>
> I would expect it to be very difficult unless you have access to
> suitable glass material, lens design, and manufacturing instruments.
> Photographic optics including enlarging lenses do not consider to
> minimize aberrations in the UV range. In addition, usual crown and
> flint glasses do not transmit UV light of shorter wavelengths very
> well, especially if many elements are used.
>
> Ryuji
> Cambridge, MA
As far as I know (have been told) glass cut uv at around 300 nm which should
give room enough for an exsposure, have a feeling that the problem is more
that of having a strong enough bulb, because a lot of energy is lost through
the "enlargemnt factor" plus the necessity of some diffusor function since
these big bulbs are not excactly point lights./ gives uneven exsposure.
What does aberrations mean ? (Sorry optics is one of my neglected fields)
Does UV behave like IR / have a different focus point ?
Halvor
(back tomorrow)
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