Processing colour photographic prints

The Photographic Services Department of the Canadian Conservation
Centre has been having trouble with a colour processor (Fujimoto CP
51) that leaves marks on newly processed colour prints. The problem
appears to be a rubber drive roller in the processor. Many of the
new prints come out of the processor with light black scuff marks on
them. They're concerned about the future aging of the prints even
after they remove the marks, and they are also worried that even
prints which appear to be unblemished may have invisible deposits
which could cause problems in the future.

The Photo Services Department documents our collection for the
purposes of conservation and curatorial records and publications,
and in order to make duplicates or facsimiles when originals should
cannot be handled or exhibited. It's important that the images be of
high quality and that they last for a very long time. So they want
to know how to avoid these blemishes.

When the roller was new (more than a year ago) it caused no
problems. But now, after frequent use in the developer solution, the
black colour on the surface of the roller rub off on the hands when
you touch it. The same type of roller roller used in the bleach
solution causes no problems. The surface of that roller has not
degraded and does not rub off on your hands.

Photo Services could buy a new roller (if they were sure it was the
source of the problem), but that would be their second new roller in
two years. A new roller costs $800 US, an amount that they do not
want to have to spend yearly to replace this part. They would like
to know if it's normal for a roller to begin to leave marks like
this as it ages. Nothing in the maintenance manual suggests they
should have to replace the part frequently. All recommended
maintenance procedures for the equipment are being followed.

Photo Services asked me, as an art conservator, if there was any way
I could determine and prove, by looking at the marks and at the
roller under magnification, that the roller was causing the marks. I
don't think that, short of getting an analytical chemist to analyse
both the scuff marks and the roller residue, I can offer any
conclusive evidence, but I promised I'd ask around to see if anyone
else had suggestions. They also asked if they could use a solvent or
detergent to clean the roller themselves. I don't know if that would
be effective--if the roller is simply degrading, won't it continue
to do so after cleaning? I also don't want to suggest they try any
anything that might ruin the roller completely.

If anyone else has encountered this problem or has any suggestions,
I'd appreciate hearing from them.

Karen Potje
Head, Conservation/Preservation
Canadian Centre for Architecture
1920, rue Baile
Montreal, Quebec H3H 2S6
Canada
514-939-7000
Fax: 514-939-7020


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                  Conservation DistList Instance 13:54
                  Distributed: Wednesday, May 3, 2000
                       Message Id: cdl-13-54-021
                                  ***