Some solutions for carbon transfer problems

Pollmeier Klaus (100561.2417@CompuServe.COM)
31 Aug 96 02:29:51 EDT

Dave wrote (offlist, so I repeat it here):

<I prepared my own pigment tissue. That was my first tissue. There was some
unevenness in the tissue - lots of bubbles and the pigment doesn't seem to be
dark enough. However, I decided that those weren't the most critical thing
because I just wanted to see how the transfer process work first and then maybe
try to perfect the tissue.>

You can avoid or kill the bubbles by spreading the hot gelatin with a comb over
the paper. Take ca. 25 ml for a sheet 8x10". The coating must be thick enough
but doesn't have to be totally even. Pigment content (watercolors from tubes)
ca. 2%.

<I soaked the pigment tissue in sensitizer (10% Pot. Dichromate) for about 2
minutes under room temperature. I did notice some gelatine actually dissolve
during sensitizing. Then I dried it in a film dryer with cool air.>

If you make your own tissue, you can add the dichromate during manufacture.
Saves time... 10% Pot. Dichr. is much too much! start with 2 or 3 % at 15C for
three minutes. I prefer a spirit sensitizer (sensitizer/ethylated spirit 1:1),
applied with a plastic foam brayer). Dries much faster...

<I exposed a step wedge with a light box (5000K light box sold in office-supply
tores). First time I used 15 minutes. Second time I used 20 minutes. The first
print looked better.>

I have no experience with this kind of light. I use special tubes with high UV
output. Did you mask the edge of the tablet (1-2-mm) with semi-transparent tape,
to get a 'safe edge'?

<For transferring to temporary support, I soaked the support (I used vellum) in
cold water (about 70 deg.), rinsed the sensitized tissue for about 1minute in
another tray, then combined the two together, pulled out and squezeed; put them
under a piece of glass and weighed them down with a bucket of water.>

Does vellum mean parchment? Never heard one had used it... Or is a kind of
plastic? Anyway, if it is water permeable, like paper, you have to give it an
extra size with hardened gelatin, ca, 5-10%, ca. 25 ml for a sheet 12x16". Give
it a glyoxal bath (2,5%, 10 min) to harden it and wash afterwards. Or: take
fixed-out bromide paper.
70F is much too warm. Take water you cooked one day before (to remove any free
air) and cool down to 60F.

<After 20 minutes, I took the tissue and support out, put them in a tray of
water of about 105 deg. I waited for about 2 minutes but no pigment ooze out,
but the tissue started to float itself off the support in the corner. I
carefully peel it off, and most of the pigment stayed on the tissue although
there was some transfer (as I mentioned in earlier message, I can actually see
the step letters of Stouffer steps, but the actual tones weren't there though.
It looked like only the deepest black and lightest white were transferred).>

Probably underexposure or uneffective transfer.

To get rid of most (if not all) problems, get Luis Nadeau's "Modern Carbon
Printing". Just a perfect manual... But even after more than ten years of
practice, I still run into problems from time to time with this great but still
mysterious process.

Klaus Pollmeier
100561.2417@CompuServe.COM