> From: Terry King <101522.2625@compuserve.com>
> Date: Fri, 13 Dec 96 23:02:12 +1100
> Subject: Salt Printing
> To: Multiple recipients of list <alt-photo-process@cse.unsw.edu.au>
>
> To salt Printers and calotypists.
>
>
> The standard recipes give potassium citrate as an ingredient of the
salting
> solution.
>
> What advantages are there in using potassium citrate, which is not
readily
> available, over citric acid which can be bought cheaply from the
> supermarket shelf ?
>
> Moreover, what is so special about tartaric acid in the VDB or brown
print
> versions of the kalitype.
>
> Could we readily interchange the three, ie tartaric acid, citric acid and
> potassium citarate?
>
> Terry King
>
Terry
Citric acid is said to give a greater contrast. I believe Brian Coe used it
when doing the massive print of Talbot negatives some years ago for the
science museum. Though I think he said he used it merely because it gave a
yellowinsh colour to the paper so that he could see that it was coated
evenly. But there are so many variables in salt printing: the type of salt
used; the quality of the silver nitrate and not least the paper used and
the sun on that particular day. Paper types as well as sun quality can
effect contrast. There is also a formula using gum arabic which from one or
two attampts gives a greyish image.
Richard Morris