Print image damage from mounting press heat

[DaFruz2]

I have been using mounting presses to flatten fibre prints (after they have fully dried on racks) for many years. Last week I went about flattening a batch using a Kennett (UK) press which I don't have a lot of experience with. I have flattened several batches, of other warm tone paper from another project previously with no issues. The prints I was flattening were of a very low key image with a black border. They were printed on Foma 542 Natura paper, which I would describe of a warm tone matt paper with a sheen – perhaps semi-gloss. A very lovely paper.

After the first few prints went through, I began noticing a sort of faint bleach patch appear along the border of the print. I immediately reduced the amount of press time by 30%, but the damage continued in the same place over the next couple of prints. I had hoped that it would clear when the print fully cooled, but it's now been a week and the damage is still there. I would describe the damage area as the sort of thing you would expect if a dark print were left in direct sunlight for a couple of years. Blacks turned to a dull chocolatey brown in the damage area. The press obviously has a hot spot in the rear right, and I let it warm up too long. I was letting the print be pressed for 45-60 seconds, at a setting of 6/10. I reduced it to 30 seconds after noticing the damage. Is this too long?

Needless to say that it is quite disappointing to have this happen at the very last step after going through meticulous archival procedures with a very difficult neg to print.

I was wondering if anyone else has had experience with this sort of damage, and if there is any way to undo it, or if there is any advice when heat flattening this particular type of paper? Could soaking and re-drying the damaged print restore it?

 

[Gerald C Koch]

Mounting presses are designed to be used at the lowest temperature setting that will cause adhesion. People used to use household irons set at the lowest (silk) setting for hand finishing. Best to use the press without heat on dry prints. When used properly for their intended purpose these presses should not effect any correctly processed prints. So you are right something seems to be amiss. You could try bleaching with a rehalogenating bleach and redeveloping.

 

[pschwart]

I have been using mounting presses to flatten fibre prints (after they have fully dried on racks) for many years. Last week I went about flattening a batch using a Kennett (UK) press which I don't have a lot of experience with. I have flattened several batches, of other warm tone paper from another project previously with no issues. The prints I was flattening were of a very low key image with a black border. They were printed on Foma 542 Natura paper, which I would describe of a warm tone matt paper with a sheen – perhaps semi-gloss. A very lovely paper.

After the first few prints went through, I began noticing a sort of faint bleach patch appear along the border of the print. I immediately reduced the amount of press time by 30%, but the damage continued in the same place over the next couple of prints. I had hoped that it would clear when the print fully cooled, but it's now been a week and the damage is still there. I would describe the damage area as the sort of thing you would expect if a dark print were left in direct sunlight for a couple of years. Blacks turned to a dull chocolatey brown in the damage area. The press obviously has a hot spot in the rear right, and I let it warm up too long. I was letting the print be pressed for 45-60 seconds, at a setting of 6/10. I reduced it to 30 seconds after noticing the damage. Is this too long?

Needless to say that it is quite disappointing to have this happen at the very last step after going through meticulous archival procedures with a very difficult neg to print.

I was wondering if anyone else has had experience with this sort of damage, and if there is any way to undo it, or if there is any advice when heat flattening this particular type of paper? Could soaking and re-drying the damaged print restore it?

- I always flatten prints at the lowest temp. Most dry mount presses have actual temp settings, not just numerals as this is critical when
using dry mount tissue.
- I would not expect 60 seconds to damage fiber base paper. I suspect the heat is making visible a processing problem.
- tip: do a first quick pass (15 seconds?) to dry a print thoroughly, then a second pass to finish flattening. Residual moisture can cause mottling.

 

[RobC]

are you placing print between mountboards when you flatten/dry them?

 

[Maris]

I use a Kennet(UK) dry mounting press for flattening fibre base photographs with the following technique:

Press at heat setting 7 and fully warmed up.
Two smooth acid-free mount boards are absolutely dried out by several squeezes in the hot press. The mount boards will act as a sponge for water vapour given off by the photographs.
The photographs are brushed front and back with a wide book-binders brush to remove every trace of dust or grit which would otherwide be embossed into the picture surface by the pressure of the press.
The photographs are placed between two acid free thin papers, then between the hot dried mountboards and into the press for a 10 second squeeze.
After opening the press the hot/dry/flat photographs get stacked face-up under a sheet of thick glass to cool.

With all the materials at hand and a routine practiced I can flatten nearly 100 photographs an hour. It's warm work.

 

[DREW WILEY]

Are you sure your prints are properly fixed and washed? The notion that part of your image appears "bleached" is odd, too much heat or not. But to
simply dry a either print or mounting board prior to using the drymount tissue, you want to sandwich it between two dry pieces of museum board and
close the press for about 30 seconds. Do not clamp it hard like you do for permanent mounting. I do not know what kind of press you have, but thermostats can go bad, so you need to check from time to time.

 

[paul ron]

Your temp is too high n burning the emulsion. As you indicated, there is a hot spot in your platten.

Using less heat and sandwiching between Matt boards should cure the problem.

 

[Rich Ullsmith]

"Flattened papers from another project with no issues."

My guess is the other project was fully fixed.

 

[john_s]

I wonder if washing and redrying the prints might restore the surface. My guess is the the silver image is still there but the surface is altered by the heat.