Re: When to tone?

From: Richard Knoppow <dickburk@ix.netcom.com>
Subject: Re: When to tone?
Date: Wed, 12 Nov 2003 06:19:14 -0800 (GMT-08:00)

> There are methods of testing for the degree of toning by using a
> dichromate bleach and for the degree of protection against
> oxidation by using a hydrogen peroxide solution. I am at work at
> the moment so don't have access to references. I will post
> something more later.

These are nicely described in the report available from IPI:

Reilly, J. M., Nishimura, D. W., Cupriks, K. M., and Adelstein,
P. Z. 1991. Sulfiding for Protection for Silver Images. Final Report
to the Office of Preservation National Endowment for the Humanities,
Image Permanence Institute, Rochester Instute of Technology.

This also gives a nicely concise description of liver of sulfur and
polysulfide chemistry (as well as information from EKC that KBT is
nothing more than 245g/L of liver of sulfur (aka sulfurated potash)).

In the different thread, I mentioned silver nitrate tests for residual
thiosulfate. For this topic, key papers are:

Crabtree, J. I., Eaton, G. T., and Muehler, L. E. 1944. A review of
hypo testing methods, J. Soc. Motion Picture Engrs., 42, 34--57.

Silver nitrate test for paper prints was adapted for film materials
and made more reliable by addressing a number of issues by Mattey et
al. and further simplified by Pope.

Mattey, D. A. and Henn, R. W. 1966. Determination of thiosulfate and
thionates in film with silver nitrate, Photogr. Sci. Engr., 10,
202--8.

Pope, C. I. 1969. A simplified method for determining residual
thiosulfate in processed microfilm, Photogr. Sci. Engr., 13, 278--9.

The film procedure is probably the best method even for print
materials if quantitative measurement is desired. Print strips should
be immersed in test solution and given ample reaction time, and the
density should be read by *transmission* densitometer though I know
it's not very easy with paper support. I remember Haist's book
described these.

To R. K.: this years Christmas gift is sent out today though it's very
early.

--
Ryuji Suzuki
"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)