RE: (long) Re: Permanence of Bleached Silver Prints

Ole Chr. Magneshaugen (ocm@eidolon.no)
Thu, 19 Feb 1998 13:49:12 +0100

The SilverLock toner was a sulphide toner, developed at IPI, with permanence
as its main objective. I have seen data on test, where different films and
paper have been treated in different toners and procedure, and the
SilverLock really had something going for itself. The SilverLock outrated
all other procedures by far. Selenium came out very poorly, especially at
the dilutions usually recommended. Areas of little silver density are
hardly affected by selenium at high dilutions. The SilverLock yielded equal
toning effiency througout the density scale.

Obviously the SilverLock is no longer made by IPI, due to availability of
the liver of sulphur which was an important compound in SilverLock.

In the report I am referring to it was interesting to see how much poorer
the TMAX withstood ageing in comparison to traditional films, and even
modern T-grain films from Ilford.

If anyone has knowledge of research of thiocarbamide as an toning agent, in
terms of its permanence raising characteristics, in relation to sulphide
toners, I would like to know about them. Thiocarbamide is mentioned as an
archival toning agent in several resources, but it would be OK to see actual
test data.

best,

-olec