Continuous Tone Positives

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From: walt goettman (wgoettman@mm.wyeth.com)
Date: 06/19/00-01:40:45 PM Z


Hello All

Is anyone familiar with this technique of mixing HC110 with paper
developer which was found at
http://home5.inet.tele.dk/artguide/uk/perfect-pos/index.html:

How To Make a Continuous Tone Positive
The lith films are orthocromatic and will not be affected by a dim, red
light. This light serves for all darkroom work without damaging the
film. Yellow or
yellow-green light is also an option, but it must be adjusted to the
positive film you have chosen (see the instructions on the package under
"safelight").

       Place the negative in the enlarger, turn it on and focus the
image on the contact frame. Turn the light in the enlarger off again.
       Cut a strip of the positive film and place it with the emulsion
facing upwards on the contact frame. Make a test exposure with different
exposure
       times, e.g. 2, 4, 6, 8 and 10 seconds.
       Develop the film in a photo tray (containing 1 litre of water, 10
millilitres of concentrated Multigrade paper developer and 10
millilitres of
       concentrated Kodak HC-110 developer) for exactly 3 minutes at
approximately 20° Celcius.
       Now move the film to the stop bath for approximately 10-20
seconds and finally to the fixer, leaving it there for about 3 minutes.
       Rinse the film brifly in cold, running water and hang it out to
dry in a peg at room temperature (you may use a hair drier after 3-4
minutes).
       Examine the contrasts on a light table. Find the area of the film
with the greatest amount of detail in both the light and the dark areas.
A new test
       exposure of half-second intervals might be necessary in and
around the best area. If the positive is too soft, double (or even
further increase) the
       amount of HC-110 developer. If the positive is too hard, mix a
new developing bath with half the amount of HC-110. Do not change the
amount of
       Multigrade developer ? only the amount of HC-110 affects the
tonal range. So, when you have determined the optimum exposure time for
the
       negative, you can regulate the contrast and tonal range of the
positive by means of the amount of HC-110 and thus produce the perfect
positive. The
       film is now ready to be exposed onto the ImagOnlaminated intaglio
plate after the exposure of the aquatint screen.

If you use one of the two mentioned films; the Ilford XP2 Super Film or
the Kodak T400 CN, the contrast level is often so low that you can
simply
develop the positive in an ordinary multigrade developer (such as 100
millilitres of Tetenal Variospeed + 900 millilitres of water for two
minutes).

Thanks

Walt


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