From: Tom Ferguson (tomf2468@pipeline.com)
Date: 04/15/00-04:23:06 PM Z
I have written about my use of color transparencies to FP4 for enlarged negs
before on this board. I use this method quite regularly. It has both real
advantages and disadvantages.
First: to the original question, this is not how I would go about making
conventional B&W prints. I only use this for alt process printing were a
very large contact size neg is needed. 20x24 inch cameras are such a big
pain ;-(
B&W neg film is cheaper, more forgiving of exposure errors, and has far
wider density range (can hold detail in very bright and dark things in the
same scene) than color slides.
A good (non super saturated) transparency film (E100N, Astia) can hold
detail from zone 3 to zone 7 (two stops under meter to two stops above).
That is 4 zones or a 16:1 ratio. Reducing the development of E-6 film
results in little more than loss of film speed.
A good B&W film can easily hold from zone 2 to zone 8 (three stops under
meter to three stops over). That is 6 zones or a 64:1 ratio. You can use
"zone system" type "minus developments" to get even larger ratios, such as
Robert mentions below.
So, what is the advantage to shooting the transparency and then enlarging
onto panchromatic B&W film in the darkroom? It is perhaps the easiest of
the optical/chemical methods for getting large contact print negatives for
alt process work. That assumes that you can either control the lighting
ratio (studio work) or simply prefer to shot normal to low contrast scenes.
-- Tom Ferguson http://www.ferguson-photo-design.com> From: Sil Horwitz <silh@earthlink.net> > > At 2000/04/15 04:22 PM -0400, Robert Schramm wrote: >> Several different photography texts I have checked say that color >> images have a tonal range of 8:1 to 16:1 at best, while black and >> white images have a tonal range of 144:1 to 256:1 at best. > > Doesn't sound right. The multiplicity of color layers should result in a > greater tonal range when extrapolated to BW. Can you give us the references > in "several different photography texts"? I'd like to check their testing > and evaluation process, as well as when the evaluations were done, because > early color films weren't much good at reproducing intermediate tones. When > I was teaching color theory, my conclusions were just the opposite! > > > Sil Horwitz, FPSA
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