Re: pinhole-discussion-digest V1 #179

Thanks for the interest in pre-flashing paper negatives. Lets see if I can
sort out the questions:

1)I've tried pre-flashing with two different cameras, a 4"x5" format about 3"
focal length, and a 5"x8" format about 9". The paper used was Arista grade 2
RC, glossy surface, cool tone. The negatives look dramatically different than
without preflashing. Absent are the large areas of blank paper white, where
there's no shadow detail (in sunny daylight exposures with harsh shadows). The
gray-scale looks more film-like than I'm used to seeing with paper negatives.
I've also contact printed these negatives, and the resulting images are much
more film-like. Continuous tone, good shadow and highlight detail.

One of these negatives was shot in overcast daylight, and the resulting
negative needed grade 4 filtration in order to get normal contrast. This is a great
change from past experience, where there's always too much contrast for the
print. Having to increase printing contrast is a good thing, for me anyway.

2) I haven't tried post-flashing, after the exposure. Not sure if it would
work, but its worth experimenting with.

3) I was using a Beseller 4x5 enlarger, column height I didn't measure, but
it was near the top. I had to experiment with different lens setting to get the
right amount of pre-flashing. Rather than try to mimick my setup, anyone
trying this should justs calibrate their pre-flash for their setup.

Basically, if using an enlarger, run the column height up all the way, set
the lens to f/16 or f/32, and pre-flash face up using contrast filter 2 for
starters. Then make a controlled in-camera exposure of a setting that you've
metered in consistent outdoor light. Develop and see results. Make sure the scene
has shadow detail that you'd normally not be able to get detail from in a
normal exposure time.

If you've preflashed not enough, you should be still missing shadow detail.

If you've pre-flashed too much, the negative will have an overall gray cast -
or maybe black, if the pre-flashing is way too much. Just experiment with
your enlarger or light source to get the right amount. You may have to put a
thin sheet of white translucent plastic over the negative, if you can't get your
enlarger light dim enough or far enough away. My initial experiment used the
lens at f/8 (way too much light), so I had the paper face down, with a 1/8"
white plastic sheet on top. It worked, but the paper fiber grain showed through
in the shadow detail, so I sent to face up, no plastic and stopped the lens
down much more, with good results.

Its like doing the initial calibrations to a newly constructed camera. Trial
and error until you see results you like.

Joe

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Received on Tue Nov 16 09:43:48 2004