From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 05/18/00-03:15:19 PM Z
Vamaza@aol.com wrote:
> ...
> I was studying a platinum print that was made in the late 70's and it had
> this usual type of staining.
Do you mean unusual? There is no usual stain as you have described.
> It was a yellow orange stain which was present
> only around the dark midtones and black areas. In the light midtones and
> highlight areas there was no stain present. I assume it has something to do
> with the ferric oxalate.
Why this assumption? I know of no reason for it to be related to ferric
oxalate.
Such a stain could be a result of incomplete clearing but it is puzzling
why it occurs only around certain areas.
Contamination with film (or gelatine silver) processing chemicals could
produce purple or orange stains.
> The platinum should not cause such a stain, correct?
If the K2PtCl4 was not completely removed from the print it may show up
as red or orange-yellow. However, one might expect more color in the
less exposed (highlight) areas. This is highly unlikely as K2PtCl4 is
soluble in water and should wash out.
> It what ways, if any, can the environment accelerate such discoloration (ex.,
> being near the ocean).
If uncleared, continued exposure may darken or yellow the print.
The paper may be susceptible to environmental conditions as typical with
any paper.
Certain humid conditions and the presence of contaminating spores may
promote mold or fungus growth which might have a orange-yellow color.
These are only guesses as without the print and some evaluation it is
difficult to know. I have never seen the type of staining you have
described.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
This archive was generated by hypermail 2b29 : 06/13/00-03:10:20 PM Z CST