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robinb
24th August 2014, 12:58 PM
Hi

I have a number of old bw pints on fb paper that i am re framing
they have some brown marks on the back which I guess means they were not properly washed

can anybody advise my best course of action to clean them up

thanks

robin

Lostlabours
24th August 2014, 03:16 PM
Soak them in water for 10 mins then re-fix and wash as per normal.

It's not just washing they probably were fixed with too high a silver level in the fixer this leaves semi-soluble silver thiosulphate complexes which break down in time.

Ian

Argentum
24th August 2014, 03:26 PM
could be caused by dampness through high humidity or lots of other things.
Old frames were often backed using pine board which is really bad as the resin can leach out. Or even some poor quality card backing board and dampness. So it may not be chemical residue in the print but could be and for that reason Ians advice is good.
I think its unlikely to come out completely and can be considered as part of the patina of an old print.

Just be very careful of the emulsion when its wet and dry very slowly, preferably face down to reduce curling. I assume its FB.

robinb
24th August 2014, 03:46 PM
thanks guys

I'll give that a go

robin

Steven
24th August 2014, 04:38 PM
How valuable are the prints? I went to see a professional conservationist many years ago because I have a collection of prints by a well known photographer that were not properly mounted and have various stains and other issues. She pointed out several problems. One is that certain moulds and other nasties that affect prints can cause a breakdoen of the gelatine. Gelatine is a wonderful substance that is solid when dry and semi solid when wet. The whole of traditional photography replies on it holding it's shape when wet and returning to exactly the same place when it dries. If this integrity is damaged, for example by mould growth, then it may simply become water soluble.... So after washing and re-drying you could just end up with empty patches. I would say scan the things first, so at least you can explore the digital repair route... Then re -wash, re- fix and re- wash again.

The brown spots could be what is called 'foxing'. This is a problem with the paper, nothing to do with the photographic process. Many old books and manuscripts suffer from this. The fix is usually bleaching, but this doesn't always sit well with the photographic image!