What causes these stains?

[Marco B]

Hi all,

Although I generally try to work as cleanly as possible in the darkroom, regularily wash my hands during a printing session if I suspect I have come in contact with the chemicals, and also wash the prints well, I occassionally have small pinkish / orange stains on the back of my fibre based prints after drying. (I have never noticed them before drying, but they may have been there, I usually have my prints face up in the trays).

See the attachment for an example, please note that that is about a 7x enlargement! The stains are NOT visible on the front. Strangely and in addition, I have noticed that it almost seems like something "ate" into the back of the paper, the stains seem to be slightly recessed compared to the paper surface...

Please note, that I (partially) sepia tone most of my prints at the present time (using a two bath FerriCyanide / Thiourea toner), but I think I have seen them on untoned prints as well, but I am not entirely sure...

Anyone have a clue as to what causes these stains, and what they will do in the long term to a print?

Marco

 

[trexx]

do you have more then one print in the fixer at a time? I suspect free sulfur complexes that form at various stages of fixing.

TR

 

[Marco B]

do you have more then one print in the fixer at a time? I suspect free sulfur complexes that form at various stages of fixing.

TR

No, never, I work to slowly for that... just one print in the fixer at any moment in time.

I recently bought for the first time Kodak Hypo Clear, which I hadn't been using before, but one of the four prints I made yesterday that went through HCA, now also shows a stain (the one in this picture).

Marco

 

[WolfTales]

No idea but I get them too from time to time. Also wondering if someone knows the answer to this question.

Whenever it happens, I swap all chems out for fresh chems and give a thorough bath to all utensils in hot water. Seems to help but never seems foolproof.

My first impression is that it is sulfur compounds caused from sepia and then selenium toner that is essentially running off the emulsion. I seem to get them if I don't thoroughly rinse and dry my prints.

 

[Hal Reiser]

When I started using latex disposible gloves while printing I began to notice silimilar type stains on my prints no matter how careful I was. I finally realized that the gloves I was using were of the powdered variety and that if my hands became sweaty the powder could drip out of the gloves without me noticing and stain the prints. Once I switched to powder free nitrile gloves the staining problem disappeared. Just a thought.

 

[Marco B]

When I started using latex disposible gloves while printing I began to notice silimilar type stains on my prints no matter how careful I was.

I never use gloves, but make every effort to avoid contact between any of the chemical baths and my hands (I use tongs) and only touch the paper in it's dry phase before the wet stage of printing.

That said, it isn't completely excluded that some drop of fixer got on my hands, but I have never seen anything like finger print style marks on the prints.

I still find it intriguing that I only see the stains on the back (although likely I more often touch the back than the front of the paper during handling beneath the enlarger), and that the stains really DO seem to be somewhat "embedded" in the paper... I just can't comprehend why that would happen, unlike, like I said, something really "ate" away on some of the paper fibres, but the stains more look like some "compression" of the paper. Just like if the paper was strongly pressed against some chemical residue, but of course, that doesn't happen in my darkroom trays... (well, I can't think of any method at least...)

 

[MattKing]

How do you dry the prints?

Do you squeegee them before drying them?

Matt

 

[Marco B]

I dry them on glass (which I clean after each drying session), by taping them down using watercolor tape. No squeeging.

 

[Marco B]

Ok, I now ran a small test. I deliberately contaminated the back of a small piece of printing paper with used fixer (the same batch that caused the above stain), and subsequently put it through the develop / stop / fixer / rinse and drying cycle.

No stain whatsover, so it seems the stain is NOT related to fixer contamination (at least not before putting it through the chemical baths).

Still leaves the option of contamination after the final rinse. I think I will do a small test for that as well, see if some fixer on the paper can turn reddish, although the whitish stains on my fixer bottle make me doubt it.

So it may be related to the sepia toning?... but what causes it, still is a mystery to me.

 

[Rick A]

I have a strong suspicion that the stain is from drying your prints on a piece of glass. The location of the stain is what makes me think this, it may be that any residual chems are wicked there due to paper drying from the outer edges inward toward center. Try drying your prints on blotters or screens(preferred) to see if it clears up. Just a thought.

Rick

 

[Ronald Moravec]

I too suspect the glass. Wash it with Windex or amonia, rinse VERY well and dry.

Pink stains come from selenium toner coming in contact with trace amounts of fix. Either go from fix to selenium with a 30 sec rinse or do the whole archival wash sequence, tone, and repeat whole archival wash sequence. I do #1 about 99% of the time. Selenium has fix in it.

When washing prints, use a print washer or simply interleave them three times in each of 8 changes of water. I suspect the back may not be getting washed.

While I interleave in one tray, I fill a second tray, then move the prints one at a time changing emulsion up to down and then back.

After 50 years of interleaving, I am too old to get a proper print washer. But my water useage is minimal as this is very efficient process. I never had a print go bad.

 

[Marco B]

Pink stains come from selenium toner coming in contact with trace amounts of fix. Either go from fix to selenium with a 30 sec rinse or do the whole archival wash sequence, tone, and repeat whole archival wash sequence. I do #1 about 99% of the time. Selenium has fix in it.

Although I occasionally use seleniumtoner, the last time I used it is quite some time ago. The glass has had quite some thorough cleanings inbetween, so I don't think selenium is in the equation at this moment.

Another funny observation is that I now noticed that the pink stain that I scanned, seems to have gone almost colorless. I can still see the outlines, but more as a very faint grayish stain.

Could a drop of USED ferryicyanide bleach cause this, as the bleach converts at least part of the silver into silverhalide? Maybe with usage, part of the silver of the images is disolved in the bleach causing a small amount of silverhalide to be build up??

If that was exposed to light, it might turn greyish eventually, like normal photo paper when not developed but exposed to light?

But it still remains strange I only see it on the back, and I almost always have the prints face up in my trays, I would expect any stains to appear on top, not the back side of the paper...

When washing prints, use a print washer or simply interleave them three times in each of 8 changes of water. I suspect the back may not be getting washed.

I would like to get an archival washer one time, but at the moment, I neither really have the money nor space to accommodate it. I do regularily swap the prints and move the tray while washing, so I think the back does get properly washed, but can't really confirm it completely until I do a residual hypo test.

 

[Stefan Findel]

Good luck with archival washers! I had two kinds: The eco type, using low water flow left TMax film sitting in pink water even after 15 minutes of washing. Means to me, that low flow isn't working. The other type with high pressure and air bubbles rising from the bottom, left yellowish stains on my sepia toned prints near the air inlets, and I feel is wasting too much water. Now I wash my prints in standing water in trays and replace water every few minutes.

 

[Marco B]

Good luck with archival washers! I had two kinds: The eco type, using low water flow left TMax film sitting in pink water even after 15 minutes of washing. Means to me, that low flow isn't working. The other type with high pressure and air bubbles rising from the bottom, left yellowish stains on my sepia toned prints near the air inlets, and I feel is wasting too much water. Now I wash my prints in standing water in trays and replace water every few minutes.

OK, well, it seems I can safe a few bucks by sticking to my current working methods

 

[Marco B]

I have a strong suspicion that the stain is from drying your prints on a piece of glass. The location of the stain is what makes me think this, it may be that any residual chems are wicked there due to paper drying from the outer edges inward toward center.

Might be possible, but I still can not fathom how after the amount of washing and water wastage (luckily I live in a country with no real lack of water, and, although I don't deliberately waste it, I am not conservative with it either when washing my prints), there would be enough residual chem left for such an obvious stain...

I even emptied my whole boiler yesterday in keeping 20C water... (needed big trays for 40x50 cm paper and needed a lot of extra washing cycles due to an additional sepia tonings of each print). I wouldn't have enough hot water for more 20C washing...

 

[Nicholas Lindan]

You say there is some mechanical damage to the paper at the site of the stain. This says it may be a manufacturing defect. Are all the prints with the stain from the same box of paper? Does unprocessed paper exhibit the same damage on the back of the paper?

 

[Rick A]

Might be possible, but I still can not fathom how after the amount of washing and water wastage (luckily I live in a country with no real lack of water, and, although I don't deliberately waste it, I am not conservative with it either when washing my prints), there would be enough residual chem left for such an obvious stain...

I even emptied my whole boiler yesterday in keeping 20C water... (needed big trays for 40x50 cm paper and needed a lot of extra washing cycles due to an additional sepia tonings of each print). I wouldn't have enough hot water for more 20C washing...

All I'm saying is that when the H2O evaporates, any dissolved impurities tend to concentrate in the remaining water. As the center of the [back] of the print is the last to dry(the face having a barrier), this is where any apparent residue will appear. The stain could possibly only be impurities in the water used to wash, rather than actual photo chem residue. Try drying on a screen, if you still have stains, then look to the paper itself, it may be defective.

Rick

 

[Marco B]

You say there is some mechanical damage to the paper at the site of the stain. This says it may be a manufacturing defect. Are all the prints with the stain from the same box of paper? Does unprocessed paper exhibit the same damage on the back of the paper?

No, they are not all from the same batch / box, and it only happens once in a while on a print. I now examined the paper with a 10x loop. I can't see mechanical damage to the paper fibres, so I think my first observations of a "dent" in the paper, was more of an optical illusion caused by the coloured stain.

I think Rick may be right about the accumulated chem residue, since it is on the back, but I still find it hard to understand considering all the washing the paper goes through...

But as I wrote in one of the other post, another interesting observation is that the stain has become more or less colorless (just a faint greyish hint of the stain left), after having had the paper lying aroung upside down with the back side exposed to light...

 

[zinnanti]

Easy answer - your hands are contaminated with fixer when handling the paper. This has happened to me. I make sure that I rinse my hands between fixing, clearing and lining up another piece of paper in the easel.

Try that and see if it helps. It's typically a problem of contamination. Though your hands my be dry, it is possible to have enough residue on your hands to transfer this.

 

[Rick A]

Easy answer - your hands are contaminated with fixer when handling the paper. This has happened to me. I make sure that I rinse my hands between fixing, clearing and lining up another piece of paper in the easel.

Try that and see if it helps. It's typically a problem of contamination. Though your hands my be dry, it is possible to have enough residue on your hands to transfer this.

If you are transfering THAT much residue to your prints then you need to rethink your darkroom hygene. There is NO reason in this world to have hands that "dirty" while printing. That aside, the OP states that the stain appears after the final wash.

 

[Marco B]

If you are transfering THAT much residue to your prints then you need to rethink your darkroom hygene. There is NO reason in this world to have hands that "dirty" while printing. That aside, the OP states that the stain appears after the final wash.

Yes, it appeared after the final wash. And although I can't preclude it entirely, I do tend to try to work as cleanly as possible, washing my hands with water and soap each time I suspect I accidentally may have come into contact with some small splash of chemicals. I use print tongs all the time as well.

Still a splash of some contaminant when cleaning up might still be a possibility, but considering I try to clean up fully before starting the final wash, it all remains a bit of a mystery when it happens. I still need to figure out or watch for if I also see it happen on untoned straight BW prints. Might tell a bit more.

Anyway, I will try to be even more prudent trying to avoid contamination.

 

[jeffreyg]

Is it possible that the "contamination" is on the easel and getting on the paper before it is processed?

 

[Rick A]

Yes, it appeared after the final wash. And although I can't preclude it entirely, I do tend to try to work as cleanly as possible, washing my hands with water and soap each time I suspect I accidentally may have come into contact with some small splash of chemicals. I use print tongs all the time as well.

Still a splash of some contaminant when cleaning up might still be a possibility, but considering I try to clean up fully before starting the final wash, it all remains a bit of a mystery when it happens. I still need to figure out or watch for if I also see it happen on untoned straight BW prints. Might tell a bit more.

Anyway, I will try to be even more prudent trying to avoid contamination.

Marko, I wasn't infering that you had dirty or bad darkroom habits, I was only responding to zinnati's admission that he has that problem. I have been following this thread from the start, and I sincerely believe that the stain is merely residue from the final wash, and harmless(unless, of course, you dont wash long enough). Have you tried drying on a screen or blotter? Anyway, good luck with your endeavors, and God Bless.

Rick

 

[zinnanti]

Just a suggestion . . . I keep a finger bowl with tap water that I rinse in prior to handling new paper. I dry with paper towels that have not touched anything else. Does the layout of your darkroom adequately separate the wet side from the dry side?

Also, I don't know if this was mentioned, but you might want to run an unexposed piece of paper through the chemistry to see whether the stains show up. Do this at the beginning of your print session. It might help isolate the problem.

Just a note regarding another type of contamination . . . my daughter was printing some RC the other night. She's relatively new to printing (15 years old). She was letting the paper run off from tray to tray, however, there was still a faint line of contamination at the edge of the paper. I tested for fog. The paper was intact. The difference, I discovered, was holding the paper at an angle during run-off versus holding it horizontal or vertical. Holding it at an angle (45 degrees) better drains the chemistry from the edges of the paper. This totally did away with the contamination.

By the way, what's your chemistry? What are you using?

Tony

 

[Marco B]

Just a suggestion . . . I keep a finger bowl with tap water that I rinse in prior to handling new paper. I dry with paper towels that have not touched anything else. Does the layout of your darkroom adequately separate the wet side from the dry side?
Tony

No, my current limited space does not allow complete separation, so that is a small bit of a weak point.

By the way, what's your chemistry? What are you using? Tony

Just the basics:

- developer, stop, fix (basic version), ferricyanide bleach, thiourea toner (for sepia tonings) and seleniumtoner.

As said, I still want to look out whether I see these occasional stain also on non-toned images... as said, it only happens "now-and-then", not on every print.