I don't know that RC has a history or a current problem like this, but I
think the suggestions offered below are excellent. I immediately thought
of
incomplete fixing or incomplete wa****ng, but mounting materials could also
be a problem as suggested ny Nicholas below. I have never had a problem
myself, but I frequently test fixer and fix with a timer then use an
effective print washer. Hypo eliminator would remove any fixer left on
the
paper. I have only seen strange coloration and fading occur as the result
of chemical contamination, usually in group darkroom settings.
"Nicholas O. Lindan" <see@[EMAIL PROTECTED]
> wrote in message
news:13ltrm5au2v3c04@[EMAIL PROTECTED]
> "Jim Stewart" <jstewart@[EMAIL PROTECTED]
> wrote
>
>> after about a year,
>> the black areas turned an ugly mottled gold
>> color. I used Ilford chemistry and Mitsubi**** Gekko
>> paper.
>
> This happens to RC paper - the reason for it is a
> matter of debate. Titanium dioxide in the paper
> reacting with UV light is one current suspect,
> sulfur from pollution or the mount material is
> another.
>
> The history of RC materials is one of
> problems followed by Kodak/Agfa/Ilford/xxx
> claiming 'we have fixed the problem'
> followed by either the reemergence of the
> old problem or the creation of an entirely
> new problem. I greet any explanation or
> solution with suspicion.
>
> Agfa RC was very prone to bronzing. I haven't seen
> any on Ilford RC but that may be a matter of luck/time.
>
> To keep it from happening again you might try using
> Ilford paper. Err on the safe side: use fresh fixer
> for 5 minutes, a hypo eliminator, wash for 1/2 hour.
> There are all sorts of fast processing methods but
> the old methods are known to not contribute to the
> problem.
>
> If the picture is in a frame then make sure you
> use acid free board for the mat and mount board -
> "4-ply 100% cotton museum board" is considered the
> safest: the core of the board should be pure white,
> not grey.
>
> --
> Nicholas O. Lindan, Cleveland, Ohio
> Darkroom Automation: F-Stop Timers, Enlarging Meters
> http://www.darkroomautomation.com/index.htm
> n o lindan at ix dot netcom dot com
>
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