> Re Peter Mumford's posting on gold toners. I have some questions
>
> 1 What is salted paper?
> 2 Do you mean that the toner is applied as a developer?
> 3 If it is used as a developer, do you still use stop bath?
> 4 What are the archival qualities of the finished print?
>
Salted paper is a very old photographic printing technique
[contemporaneous with the daguerrotype]. It is a method of applying
silver nitrate and some form of salt [chloride] to paper to render it
sensitive to light.
No developer is used. The image is formed by intense ultra-violet light
alone. The usual steps involved in processing salted paper are:
A] wash, 10 - 20 minutes
B] tone, usually gold but platinum works well also.
C] fix, 10 minutes in 14% sodium thiosulphate
D] wash/hypo-clear/wash, to archival standards
An untoned salted paper print looks yellowish. Most people prefer a
toned print. No acid stop bath is used; it would spoil the fixer, which
must be neutral or slightly alkaline.
My knowledge of printing out chemistry is not that complete, but this is
the archival status of salted paper as I understand it:
A salted paper print can never be quite as archival as a print with a
gelatin emulsion or one in which the image was "developed out". The
silver molecules which form the image are so small that they are
vulnerable to atmospheric contamination, especially sulpher dioxide.
So, don't store your salted paper prints near a coal burning furnace!
It is possible to remove virtually all of the fixer in processing,
however, with normal archival washing.
The best reference on salted paper is the out-of-print ALBUMEN AND SALTED
PAPER BOOK by James M Reilly, published by Light Impressions in the
1980s. Lots of 19th C. photo books describe the technique also.
THE KEEPERS OF LIGHT, which is in print, by William Crawford, published
by Morgan & Morgan, is pretty good too.
If you try salted paper, best of luck and perseverance, you will need it!
Peter Mumford