Help to diagnose a problem
Three months ago I hung prints of some of my better b&w photographs in my office/studio at home. Some of the prints have begun to develop patches and blotches, sometimes accompanied by a shift to sepia. Most of the blotches are light but one or two are dark. Other prints are for the time being apparently OK. The question is of course why because there's clearly something here that I need to control. The obvious suspects are the environment, the frame, the mounts, the print-making itself, and light. A little information about each
The house is 75 years old, and the room in which the photographs hang had been painted about a month or so before hanging. The wallcovering has been there for 20 years, periodically painted.
They are framed in black Nielsen Classic frames and with the exception of the window mounts ( see below) everything in there was supplied with the frames.
The mounts were admittedly bought in a hurry and are Daler-Rowney white-core ph neutral mount board. This is not claimed to be archival . But the damage is not confined to areas of the prints near the board and there is no apparent damage to the substantial area of paper actually in contact with the board. All the problem lies within the mount window where the image is.
The prints are made for me on Forte Polywarmtone fibre semi-matte and are untoned. Other prints from the same batches kept in archive boxes and/or photo-paper boxes are OK so far.
All these prints have been through a flatbed scanner a couple of times- but so have others that appear undamaged.
The room is north-facing so no direct sunlight. The room has multiple low power halogen spotlights. There is no apparent relationship between how these lights are angled and tyhe prints that are starting to discolour/blotch.
Any thoughts please? Clearly I can get more prints made, but there doesn't seem to be much point until I'm sure this won't re-occur.
perhaps, a lack of proper washing. The break down can occur at varying times.
I don;t think the other materials are old enough nor in place long enough to bring about a break down of the print.
My first thought was inadequate washing, this would have or could have shown up if the prints had been toned, but as that is not the case , you are just beginning to see the effects.
I would take these back to whoever printed them and talk with them regarding their workflow, etc
This will fall into either of the following: Either incomplete fixing or inadequate washing.
"When elephants fight it is the grass that suffers"
IRAQNAM is Bush's legacy
Classic sounds of inadequate fixing - especially the sepia toning: this, I think, is printing-out of unfixed silver compounds.
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Originally Posted by David Henderson
Are these prints covered with glass?
My first thought is "environment". Do you know what type of paint was used? I know there has been talk of oil-based paints out-gassing and the phenols released having a bad effect on RC prints - and I can imagine that Fibre prints would not be immune. Glass would slow the attack, but not prevent it completely. It sounds, also, that the window mat is protecting the surface somewhat.
It is possible there is an accumulative action ... borderline incomplete fixing and washing - followed by chemical degradation.
Ed Sukach, FFP.
Thanks for the replies so far. It might help if I added the following. Most of the paintwork in the room is water -based .
If, as seems possible, the problem is fixing/washing, then would this be more apparent/apparent more quickly on prints exposed to light than those kept in boxes. If this is the case then I'd be reasonably convinced that this is the answer.
Very much so: it's the action of light on the unfixed proportion of the emulsion that causes it to print out.
Originally Posted by David Henderson
You can check with a residual fixer test on the border of one of the prints. I think Photographer's Formulary sell one.
In their seminal article titled "How to Fix and Wash for Permanence," ("The American Annual of Photography, 1944"), Crabtree, Eaton and Muehler (Kodak Research Laboratories) reported that heat and humidity - not light - accelerated the deterioration of the silver image caused by inadequate removal of hypo residues. The problem you describe sounds very much like "sulfiding," and is owed precisely to the cause identified here and by others responding above. I do not think your problem can be due to incomplete fixing because if that were the case the images probably would have darkened long before you managed to get them into their frames. I would not rule out that possibility, however. Obviously it is important that fixing be complete and that problems can result when a print is removed too early from the fixing bath. A contaminated fixing bath can also be responsible for staining, but that explanation seems out of order here given your account of the problem. If your prints are not dry-mounted and if the problem you describe is owed to retention of hypo residues as suspected, they can be treated (i.e., fixed twice, cleared, and washed) to arrest, or at the very least slow, further deterioration; however, the possibility of making new ones exists and doing so would seem a better alternative. As you probably know, there are simple colorimetric tests for checking residual hypo levels in prints to assure that their washing is complete. You might consider resorting to those. The careful choice of fixing agent, the use of either a hypo clearing agent, hypo eliminating agent, or both, and good washing technique are all factors affecting the removal of hypo residues and therefore the stability of the silver print.
Are the prints overmatted to avoid contact with the glass/acrylic?