Thanks again for your reply. I think my gelatine concentration is too low,
and that has caused it to dissolve during sentizing. You mentioned that 70
degrees is way too high, so I will try to lower the temp. during sentizing
next time. And I have probably overexposred the already thinned pigment, so
the whole tissue get hardened. I will run more tests and let the group knows
about my finding.
>> Pigment content (watercolors from tubes) ca. 2%.
About 2 gr. per 100 ml? or 2 ml per 100 ml?
>> 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 thought I read somewhere like 2-3% with ammonium Dichr. but 10% with Pot.
Dichromate? I have never heard about spirit sensitizer? Is ethylated spirit
the same thing as ethyl alcohol that one can buy from a drug store?
>> Did you mask the edge of the tablet (1-2-mm) with semi-transparent tape,
to get a 'safe edge'?
I didn't. I masked it with an opaque tape. I will try semi-transparent black
plastic as mask next time.
Dave Soemarko