Richard Knoppow (dickburk@ix.netcom.com)
Tue, 25 May 1999 01:46:45 -0700
At 01:35 AM 5/25/99 -0700, you wrote:
>At 03:57 AM 5/25/99 -0400, you wrote:
>>
>>
>>On Tue, 25 May 1999, Richard Knoppow wrote:
>>> Nelson also states "Toning baths containing hhypo and alum and also
baths
>>> in which gold chloride was combined with these constituents have been
known
>>> for many years..." but gives no references to any. I know of the use of a
>>> separate gold toning bath to modify previously sepia toned prints but do
>>> not know of any other hypo-alum type toners which also contain gold
>>> chloride. If anyone out there does I would be glad to have a reference
>to it.
>>> It is curious that his instructions say to return toned prints to the
>>> fixing bath for five minutes. No rason is given for this. Kodak and Ansco
>>> repeat this except that by the 1963 edition of Kodak's Processing
Chemicals
>>> and Formulas booklet this instruction has gotten lost. This is typical of
>>> what happens when you get too far from original material.
>>
>>
>>The theory for refixing, or one of them, is that some silver from the
>>hypo-alum bath might lodge in the paper, and darken in time. By re-fixing
>>that would be dissolved out.
>>
>>Judy
>>
>>
> That makes sense. Both coventional hypo-alum and Nelson's have silver
>dissolved in them and gain more when they are used.
>----
I answered that too fast. Hypo will remove any silver which becomes
re-halogenated. I am nost sure what mechanism is in this toner which would
result in that but can see the possiblilty for it.
Any re-halogenated silver would certainly have to be removed for the
image to be stable.
----
Richard Knoppow
Los Angeles,Ca.
dickburk@ix.netcom.com
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:35