"Thor Lancelot Simon" wrote in message
...
In article
,
Richard Knoppow wrote:

contrast filter. Find the exposure for a good print and
divide that by the ratio of paper speed to film speed.

That would be, of course, "the exposure for a good print
of the same size as the lighted area cast by the enlarger
set to cover the contact frame" -- the exposure with the
enlarger column at the same height, basically. I'm sure
Richard knows this but I got it wrong the first time I
tried this process so I thought I should elucidate.

Otherwise you will have to find the exposure by making a
test strip, that is making several exposures about one
stop
apart (each double or half the last). You really only have
to do this once to calibrate the setup.

This is what I have always found simplest.

Slow, fine grain, pictorial film works fine but most
35mm negative films have a pigment in the support which
can
not be removed and makes the slides just a little darker
than the clear support on the printing film. Not a real
problem but you should be aware of it.
For projection the positive needs to be rather
contrasty
compared to normal negative contrast. Most of the very
slow
fine grain films are inherently contrasty and its possible
to get the necessary contrast and high shadow density with
films like T-Max 100 by processing them is somewhat high
contrast developers like Dektol.

Another option which occurs to me is to use Kodalith. Is
it
still sold in 35mm roll film? For the longest time, it
was,
but under a different (and strange) product name. It does
not
have a pigmented base, and if developed in a very dilute
developer (HC110 dilution F works; POTA would probably
work
better) will in fact give negatives of slightly higher
than
standard contrast. It's also *very* slow, and can be
handled
under a dim red safelight. Perhaps it is almost ideal for
this
use. The disadvantage is that more work will be needed to
calibrate exposure and development since Kodak's tables
won't
be helpful.

What I did last time I needed nice snappy slides from
copied
small format negatives was develop normally and then
intensify
with very strong selenium toner (1:3). This gives a color
change, which is not ideal, and is wasteful of the
somewhat
expensive toner, but I was in a hurry and it got the job
done
with the materials I had on hand, and I didn't have to
recalibrate
my development system for some oddball developer like
Dektol 1:10.

Chromium intensifier, if you can still get it, would
probably work
better.

The exposure ratio I used is one Kodak recommended for
calculating exposure when copying. Whte paper is placed on
the easel and measured. The exposure is then multiplied by a
factor of 5. Actually, this is the same as making the
measurement with an 18% gray card. In the case of an
enlarger the light measured is that light falling on the
film so some correction is necessary.
I like the idea of using lith film. By choice of
developer the contrast might be made the same as positive
printing films. Kodak Fine-Grain Release Positive used to be
dirt cheap and came in 100 foot spools. No more but there
may be FGRP available outdated. Because it is so slow the
chances are it can be quite old without being fogged. Its
ideal for making B&W slides from B&W negatives but won't
work for color negatives because it is sensitive only to
blue light. In fact, it can be handled under a red
safelight. Some lith film is blue sensitive but panchromatic
lith film has been made (maybe still?) and might be quite
useful.


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Richard Knoppow
Los Angeles, CA, USA