Brown chemical stains

Hey there!
If you have checked my other posts, I've been able to get a parodinal recipe adapted to my needs. To get around problems with this new developer recipe, I'l quickly write it so that you know what's in it.

Rude Rodinal - C:
- 15 g Caustic Soda drain cleaner pelets
- 2.5 g paracetamol. (Tylenol or the like)
- 2 g vitamin C tablets (lemon scented)
- Tap water to make 237 mL

I've had no problems whatsoever with my developer, but lately I've been having severe brown stainings on my Kentmere RC deluxe glossy printing paper.

Some research showed me it wasn't fog, but rather a chemical stain, probably caused by action of decaying developer. I've prepared several freshly made batches of my recipe above, and I still get this obnoxious degree of base staining. I thought it was the fixer but I made a new dillution and it seems to have no effect on the stains. I use ILFORD rapid fixer 1+9, for about 40 seconds. I consider my negatives are the size of a 35mm frame, and so it takes much less time to fix them, though it seems like I could still be underfixing.

I can see the problem appears to happen in my developer tray, though. After all the exposed areas are fully developed, the base starts to have this nasty brown color. Maybe it could be the developing agent present in the emulsion, which might be decaying. I'm not sure. I'm going to prepare an alkaline solution to activate it without any help of external developing agents and post the results.

As for the fingerprints, I'll be getting tongs ASAP, and also be using latex gloves while manipulating tha paper, so that's a (kinda) already solved issue.

Any ideas on how to get around this?
Any help would be highly appreciated.

Thanks beforehand.

Max.

PD: I attach a photograph showing my case. Left strip is unexposed (not even shone by the safelight), the right negative was a couple of days into a camera before being taken to the field and exposed for 5 s. (Exposure is not correct, but, hey, we're talking about that ugly brown color on the highlights)

If you develop film, the developed silver halide grains release bromide and iodide - these are powerful restrainers. Photographic paper is mostly chloride and to some extent bromide based, so papers will release weaker restrainers over time. This could - at least in theory - explain, why you get fogging with paper, but not with film.

Try to add Potassium Bromide in increments of 0.5 g/l and check, whether the brown stain no longer appears. With the images you already have, you could try salvaging them with a weak bleach.

You might have some sulfur contamination in the developer. Frankly the scented vitamin C tablets sound dodgy to me; preferably use pure vatim C powder.

Perhaps you have fog on the film as well but it doesn't show very clearly against the natural b+f.

koraks said:

r. Frankly the scented vitamin C tablets sound dodgy to me

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To me also, especially if you know that citric acid is used as a stop bath. So your developer contains something (other than water ) that is used as a stop bath as well

My stop bath is vinegar in water. Not measured, just a splash and the solution smells to vinegar a little bit. Maybe it's not working...
Citric acid is not the same as lemon scents. I knew I had to specify my tablets were lemon scented because that couod be part of the thing. I really don't think having acid in my dev's recipe would be critical, since the caustic soda would take care of it. I'm pretty sure the bitamin C in my developer is sodium ascorbate, and nor ascorbic acid.
I tried filtering the undissolved fillers and that gave me a solution to certain white specks on the photograph I previously posted.

Rudeofus said:

papers will release weaker restrainers over time

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That is interesting. Are you sure this is fog and not staining? The color is uneven throughout the paper, and it's also different in color from the silver. I think it's more of a chemical stain.

koraks said:

You might have some sulfur contamination in the developer.

Click to expand...

I'm thinking where the sulphur could come from. What's your bet? Maybe something in the vitamin C tablets... Or my tap water.

koraks said:

Perhaps you have fog on the film as well but it doesn't show very clearly against the natural b+f

Click to expand...

If I can't see the fogging, what's the brown color them? I might have some fogging, because I'm not the best regarding light getting into my darkroom.

Using restrainers would help with fog, but would it help with staining? I have no bromide available, so I can't add that. Benzotriazole is another thing thar would seem to solve the issue but it's far out of reach to me rn. I thought, though, on using sugar, like in the good ol' days of tintype ferrous developers.

I added 5 tsp of sugar (fructose) to my previolusly made solution. The development was much slower but the dmax achievable didn't change. It just took much longer. We'll see if it stains.
I also thought on changing the recipe to use less paracetamol, but the development was so terrible I had to get back to the original recipe.

I will try to dip the paper in a solution of just caustic soda ans see if the problem is already on the emulsion itself. I'll make my stop bath again, this time measuring concentration.

Ernst-Jan said:

To me also, especially if you know that citric acid is used as a stop bath. So your developer contains something (other than water ) that is used as a stop bath as well

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Most color developers are pH adjusted with Acetic Acid. The presence of Citric Acid is nothing bad in a developer as long as it's pH is correct.

Ernst-Jan said:

To me also, especially if you know that citric acid is used as a stop bath. So your developer contains something (other than water ) that is used as a stop bath as well

Click to expand...

Vitamin C = ascorbic acid, which is not citric acid.

Máx Arnold said:

I'm thinking where the sulphur could come from. What's your bet? Maybe something in the vitamin C tablets... Or my tap water.

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I'd suspect the vit.C tablets sooner than the tap water when it comes to sulfur impurities. But it could be anything, really - it it's indeed a sulfur issue. It's hard to tell. These are the woes of DIY chemistry with store-bought ingredients: most of the time it works OK, but if you're running into trouble, it's going to be hard to nail it down due to lack of proper datasheets of the ingredients.

koraks said:

Vitamin C = ascorbic acid, which is not citric acid.

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I know, but he was talking about lemon scent. Thus I thought there could be citric acid in his developer.

Citric acid is pretty much odorless. The lemon scent is likely an ester of synthetic origin that is chemically not related to citric acid.

Máx Arnold said:

That is interesting. Are you sure this is fog and not staining? The color is uneven throughout the paper, and it's also different in color from the silver. I think it's more of a chemical stain.

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If you can mix a quick batch of Farmer's reducer, or try some C-41/E-6 BLIX, you could distinguish very quickly between image silver and Silver Sulfide. Here is, why I think you have fog: sulfur toner is an extremely powerful fogging agent. If there was anything in your developer capable of creating Silver Sulfide, most likely all your photographic materials would have turned completely black.

Sulphide... Sulphide...
I think my paper is indeed fogged! I made a test, submerging some unexposed paper pieces into 1) caustic soda alone, 2) caustic soda and vit. C tablets and 3) caustic soda and paracetamol tablets.
What I found out was that the staining was proportional to the strength of the developer. Ascorbate is in itself a mild developing agent, so there was staining, and it was worse with the p-aminophenol.
I'd suggest to myself using some benzotriazole, but until I can get my hands on some, we're out of luck. I'll try with sugar again, and see the results.

Also, I could notice the fogging being more prominent where my fingertips touched the paper.

Btw, I have to see when my paper is getting fogged. For what I can see there is no way my paper could get fogged by light. Maybe I'm wrong. What are your recommendations regarding light leaks and paper handling?

David Lyga as provided the most complete, concise and workable procedure I have ever seen during my 10+ year voyage into photo chemistry. A followup post by himself in this thread describes the procedures relevant to photographic paper.