Purple spots on Forte PWT

[ooze]

Hi,
I'm printing a series of photos on Forte PWT fiber paper and occasionally run into some frustrating problems. The pictures are printed on 30x40cm paper with a wide white border. After letting them air dry over the night I find that purple spots, varying from vague to very distinct, have developed on parts of the border of some of the prints. The thing is, of two identically processed prints from the same box of paper, one develops these spots, another one doesn't (the ratio is more like 1/3 or 1/4). And the spots aren't visible while the print is still wet.:confused:

The processing is 3 minutes Dektol(1+2), 30 seconds stop bath, 2 minutes Ilford Hypam (1+9). Then a short rinse followed by several minutes in Hypo Clear. Finally a 60-90 minutes wash.

I wonder whether anyone has had a similar problem and hopefully a solution. No other paper, including some of Forte's (like Polygrade or Fortezo), has caused me this much headache. I'm in the middle of the project and ideally don't want to start all over from scratch with another brand.

Cheers,
omar

 

[fschifano]

Sounds like you have a contamination problem. Developer carried over into the fixer by fingers, tongs, etc. I've seen this happen when I get sloppy with other papers.

 

[ath]

This is a known problem with PWT. I experienced it myself. Use fresh fixer at film strength and don't fix too short. I fix at least 2min at a dilution of 1+3.

 

[ooze]

Thanks a lot Andreas. Will try your suggestion tonight.

 

[tim rudman]

Thanks a lot Andreas. Will try your suggestion tonight.

I would be very interested to hear your findings.
I have noticed this occasionally, but much more pronounced with lith printed Fomatone which is Se toned. Mostly there is no problem but then, just occasionally, a run of prints will be covered in a rash of blue 'measles'.
The spots can be faint, small and sparse, or highly obvious, large and florid. I always use fresh film strength fixer in a 2 bath regime and I don't think this can account for what I have seen with lithed fomatone MG. I suspect it is a batch / quality control issue, but can't be sure.
Tim

 

[Photo Engineer]

Dark spots on baryta (FB) papers can take place if there are high levels of contaminants in the baryta (barium sulfate) itself. Barium oxide will cause blackening of the emulsion. It seems to be worst with chloride emulsions and decrease in effect as bromide is added to the emuslion. I have never seen purple, but it could be.

If this is so, then the baryta itself may be the problem.

The clue is to have the same paper on baryta and RC and you will see the problem on the baryta but not on the RC. Otherwise, this is due to something else.

Just a wild guess, as I have been running into problems with defective sheets of plain baryta FB.

PE

 

[ath]

PE, my purple spots (very faint, vanishing after 24 hrs) were on RC PWT.

 

[ooze]

UPDATE

I've been following Andreas' suggestion by using film strength fixer (Hypam at 1+4) with 3 minutes of single bath fixing. So far I haven't had any of the problems mentioned before.

Thanks a lot Andreas! That was a very helpful tip.

Cheers,
omar