From: Keith Gerling (keithgerling@att.net)
Date: 12/12/01-06:55:22 PM Z
Joachim asks:
>I have never had a clear
>understanding of the difference between Van Dyke and kallitype - could you
>explain? Thank you. Joachim
They are similar processes, and to add to the confusion, Van Dyke prints are
sometime referred to as kallitypes. True kallitypes are made by sensitizing
paper with solutions of silver nitrate and ferric oxalate, and after
exposure, developing in a bath of Sodium Acetate, Rochelle Salts, or a
number of other agents. Van Dyke prints are made from one solution: A mix
of silver nitrate, tartaric acid, and ferric ammonium citrate, and the
exposed print is "developed" in water. Van Dyke is easier, but you're
pretty much stuck with the same brown color. By varying the developer,
kallitypes offer a greater range of tones.
There are plenty of web-resident sources of information on these processes,
that do far better justice than my capsule summary. One place to start is
Dick Sullivan's site: http://www.bostick-sullivan.com/process.htm which has
papers on many processes, including a good one on kallitype. For Van Dyke,
there is this: http://unblinkingeye.com/Articles/Vandyke/vandyke.html
Keith
This archive was generated by hypermail 2b30 : 01/02/02-04:47:33 PM Z CST