Two methods of sensitizing for Direct Carbon

Getting deeper into this endless subject,
Two distinct ways of sensitizing in a Direct Carbon process.

 One. For Direct Carbon which resembles the gum process the sensitizer is
mixed in with the colloid on coating. Am I correct in assuming that a pure gum +
pigment coat cannot be sensitized after drying....the gum would be washed
away by the dichromate? (Judy ??)

Two. For the Fresson type system the prepared paper is dipped in the
sensitizer, dried and then exposed. I seem to remember that the Art Chakalis Direct
carbon system works this way containing a mixture of gum and gelatine and etc.,
          The I.C.I (Interface Carbon Imbibition) prepared paper has no gum
content whilst using a gelatine mixture. It is sensitized by dipping in an
ammonium dichromate solution which may range in strength from 0.015625% ( 1/64th
%) right thru to 4%.( or even higher) This gives you quite a flexible facet
of a process which may be varied to suit negatives of different densities and
contrasts.
                        A few more clues. Cheers. John- Photographist.
Received on Sat Mar 13 17:38:18 2004