Carbon Questions

[paradine]

Yes, bump up your gelatin to 100grams. Try that for a few tissues. Then try backing off on pigment to say about half of what you used (keeping gelatin at 100g). It's best to work with one variable at a time. Remember to keep really anal notes!

With the pigment, I understand that the more pigment added, the higher the contrast? Would the contrast be effected greatly by dropping the pigment 50%?

Glass can be used as a final support for carbon without coating ... but requires special cleaning ... Bill Winkler has an article on Lightfarm detailing his process:

You can also prepare it with Silane Glass Treatment ... Bostick and Sullivan carries it:

Also try searching Bostick and Sullivan's Advanced Carbon forum:

Thank you for the links those are very helpful.

before i switched to tray sensitizing due to having a baby in the house and the acetone fumes being overpowering, i used to measure out say 10ml of dichromate + acetone 1-1, and pour it over the tissue to swamp it and just gently pushed it around with a foam brush.

to prevent streaks the tissue must remain soaked and not be allowed to become dryed at all whilst brushing.

tray sensitizing is a lot easier, and less smelly, just refrigerate 1 litre of cold water with the appropriate percentage of dichromate pre mixed into the water, pour it in a tray and imerse the tissue for lets say 2min, pull out and gently squeegee. hang to dry.

occasionally pass the dichromate through a muslin cloth to prevent contaminates, top up if necessary, i have litre bottles from .25% - 2% dichromate

+ if more contrast is desired than .25 % then just shorten the soak time from 2 min - 1 1/2 min etc

hope this helps

I'm really new to carbon and using potassium dichromate in general to please bear with me. Right now I'm using about a 6% dichromate solution, would contrast be greatly effected by using a lower percentage or does the pigment have more control in that aspect? Would printing times be effected as well?


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Thank you everyone who has responded thus far, your posts have been very helpful and informative.

[paulie]

pigment will boost your balcks in the print and dichromate generally effects the highs/seperation
there only so much dichromate % makes a difference
but combined with pigment load you should be able to print almost any contrast neg

one of my favourite techniques is pre flashing the tissue before exposure, ruins the white border but really adds a tonal beauty to the print

your neg of course effects the overall contrast

better to get the neg right first