Writing and labels are recommended to be confined to non-image areas on the back of the print (just in case something goes wrong.) When I was just getting started 30+ years ago, my lab in Canada (under the direction of Dr. Klaus. Hendriks) was doing a writing instruments on photographs project. This would've been around 1985 or so. Pigment pens were just starting to appear on the market so they weren't included. Nothing met all of the requirements for acceptance. Some bled in water, so wicked right through the print, a number reacted with the image on the other side. At the time, they made a "best of the worst" list. I don't recall that the study was ever published. LC's stamp ink, I've heard is good, but takes a long time (one to two weeks) to dry. The final recommendation was to stick with graphite pencil if possible. (RC papers eventually had a bit of tooth added to the back so that they could take pencil.) While the method is wonderfully inert to the photographs, it's like labelling the fuse box in pencil. In a few years, you can't read what you wrote. 

ISO 18902 includes some requirements for inks and adhesives to meet to be considered to be safe to use on photographs so that might help. If you photographs include inkjet prints, then I would be very careful about applying adhesives the back (in this case, pressure sensitive adhesive tape). We have been told of, and have observed, a number of inkjet papers develop a yellow stain on the front when adhesives are applied to the back. It seems to be possibly a three component problem requiring more than just the print and the adhesive. One print that we looked at had been rolled on a cardboard tube that had some random tape wrapped around it and the rolled print sat in storage about a year. The large print was then examined for exhibition and hung for a short time when it was observed that there were yellow lines in it. The yellow lines corresponded to the tape on the tube. But didn't appear in storage and this leads us to think that it might require a third component for reaction.

Good luck.

-Doug
Douglas Nishimura
Image Permanence institute
Rochester Institute of Technology
1+(585)-475-5727
1+(585)-475-7230 (fax)
1+9585)-475-5199 (general)
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-----Original Message-----
From: Records Management Program [mailto:[log in to unmask]] On Behalf Of Martin, Deborah L
Sent: Wednesday, October 14, 2015 12:26 PM
To: [log in to unmask]
Subject: Re: writing on the backs of photographic prints

Interesting timing on this question.  We just drafted a plan to do the following to declassify archival photographs, so I'm also very interested in any comments/recommendations on this question.

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