A positive form negative

"piterengel" wrote in message
...
Hi everybody. I need for a certain work to obtain some
positives from
negatives. I can't treat all film with positive method,
because a part
of photos must remain negatives. I have a Contax Auto PC
Bellow with
slide duplicator, and a RTS II camera. Photos are taken
using an
Ilford Delta 100 film, developed in ID11. I want to use
the same film
for positives. My questions a

- can I find somewhere a manual for PC Bellows?
- Is it better to use natural light of TTL flash light to
make
positives?

Thanks all for the help.

Ziocalepino

There are several ways to do this. If you are working
in B&W (and it appears you are) you can scan the negatives
and make positives using a printer similar to the way
enlarged negatives are made for alternative processes
printing. You can enlarge onto slow film using an enlarger
with some attenuation of the light, or you can copy using a
view camera and illuminator for the negative. For same size
transparencies you can contact print.
Unfortunately, the best film for B&W postives, Kodak
Fine-Grain Release Positive, is no longer made in any size
other than 35mm. However a number of slow films will do OK
provided you can adjust the exposing light. If the positives
are for direct viewing or projection they must be of rather
high contrast and have high black density. 100T-Max and
Delta 100 are good for this since both can reach quite high
Dmax and high contrast. You will probably want to use a
developer like D-19 or Dektol. I am not sure if there is any
data for such use of these films so you will have to
experiment to find the correct exposure and development
times. For positives for direct viewing the development will
be similar to print development, that is to "completion" or
to the highest Dmax the film is capable of. Some variation
is possible to adjust the contrast to match the negative.
For making same size positives just use a glass sandwich
and contact print. Leitz used to make a neat little contact
printer for just this purpose. The only problem with
printing onto panchromatic film is that you can't use a
safelight. I think Ilford makes an orthochromatic film which
would allow the use of a red safelight.
Note also that nearly all B&W negative 35mm films have
some pigment in the support which is not removable or
bleachable. This reduces the brightness of slides a bit but
unless you have other slides which are on a clear base no
one will notice.


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Richard Knoppow
Los Angeles, CA, USA