Terry King wrote:
> You also say:
>> 1. Better separation of tones in shadows and highlights, in order to
>> compensate from the compression of these values that is inherent in
>> the long, flat shoulder and toe of the Pt/Pd D/Log E curve.
> Is the fact that one can obtain good separation of highlights and shadow
> detail in Pt/Pd prints from in camera negatives with a density range of
over 2,
> by controlling the exposure and development of the negative and the mix of
> the sensitiser, at variance with what you say, or are we just using
different
> means to obtain the same objectives?
Even with an in camera negative ideally exposed and developed for Pt/Pd, I
often (in fact, usually) want still more separation of highlight and shadow
tones than a straight print of this negative will provide. So, I use the
masks to augment the separation of tonal values that is already present in a
good negative.
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Peter Marshall commented:
> I have been struggling today to read numbers in the shadows that I know
> were clearly visible when I took the photos but do not appear on the
> negatives. I could have exposed to make them visible but then the
> highlights would have been over the shoulder of the film ...
It has been my experience, at least with the TMax films, that it is pretty
hard to overexpose enough to get highlights onto the shoulder of the D/LogE
curve. I have tested TMax400 and TMax100 with step tablets/densitometry
etc. Both films are linear--off both the toe and shoulder of the curve--over
a range of about twelve stops. With proper exposure and development, you can
contact print a step tablet onto TMax and record all 21 steps (and then
some) onto the linear portion of the curve. Thus, these films have an
enormous capacity for overexposure. So, unless you are dealing with extreme
lighting conditions (e.g., an egg in direct sunlight along with a black cat
in deep shadow in a nearby cave), it is usually possible to overexpose to
insure good shadow detail and still have good separation of highlight values
in the negative. This is the approach that I use.
Of course, printing such a negative is another matter. This is where I find
that masking techniques, either with my acetate sheets or with digital
methods, are most helpful in making sure that both extremes of the tonal
scale are expressed in the final print.
Charlie Palmer
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