COBBLER'S
PAGE
As a
subscriber to the American magazine' Darkroom Techniques'
I was surprised to see a query in the letters page from a
CRC member residing in Scotland. Not surprised must you
understand because he came from Scotland or that he was a
CRC member, a bit good publicity does the club no harm.
It was the nature of the query. It was to do with
contrast control when printing from colour slides ie.
reversal printing. Could the contrast be controlled
chemically? The surprise was that the query had to be put
so far a field when the answer could be got from members
of the Club. We have a technical officer and several
members who have first hand experience of just this
problem.
The answer went into the theory of how
it should be possible but in practice does not work. The
first question I would ask is What is the aim? If it is
to produce good colour prints work with negatives. All
the saturation of colour and tonal range is available
more easily. Slide printing introduces problems which
cannot be overcome to produce comparable results. This is
assuming the aim is the best possible in an amateur
darkroom.
I would stress amateur as opposed to the
professional who has access to masking for correcting the
inherent contrast and colour in the original slide and
can handle small format: even then they prefer to work
from larger format even now. Often you have a slide that
looks very good when projected, lots of colour, strong
lighting giving shadows and highlights with detail just
visible. Indeed it is this ability of the projected image
to cover such a brightness range that makes it unbeatable
as a picture medium. Seeing a 6 foot picture of a good
slide in a darkened room is stunning. Reducing this to
even a large 16x12 print can be a big disappointment.
Some control is available. It is
possible to produce masks to compress the contrast as
explained in our magazine several times in the past,
using lith film or other. But they do not control colour,
and anyone who has tried (as I have with limited success)
to register 35mm originals with a mask will know it is
time consuming and frustrating but it does work to a
certain extent.
All this may sound negative but it is
possible to get good prints from slides, I have seen some
beauties produced in the amateur darkroom. The secret is
choosing the right slide to print.
a) the contrast range must be lower, b) the colour
contrast condensed, c) it must be sharp, not contrasty,
which usually means it is NOT the slide that looks superb
on projection. Ideally, they look denser and flatter than
normal with detail in highlights and shadows. When
printed the result is an increase in contrast. So it
stands to reason to pick slides that are improved by the
reversal process rather than choosing slides that rely on
contrast and colour saturation when projected.
Forget chemical contrast control if it
were so easy negative processes would have long
disappeared. It does not work. Altering the make-up of
the developer affects colour balance and the results look
degraded. Anyone wanting to know why could buy 'American
Darkroom Techniques' for a very detailed explanation.
It is possible to have your favourite
slide professionally printed to a very high standard even
if the original is contrasty as they use professional
masking techniques or even copy negatives. So, why have
all the hassle in the darkroom to end up with a
disappointing result?
Have a go by all means and if you pick
your slide with care, bearing in mind the above remarks,
you will be delighted.
Density difference between detailed
highlights and shadows in a scene should be no more than
4 stops. Project onto a flat white card and spot meter
the image. Even in this limited range a certain amount of
burning in and holding back will be necessary when
enlarging and so can affect the colour balance.
Happy enlarging!
PS I would be interested to know how our Scottish member
went on and hope he will share his experience with us. I
always welcome letters and appreciate feedback.
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