My Darkroom mystery

[don sigl]

As developer is used it begins to change color turning from a yellowish-tan to a brown color. Even when darkly colored it will still produce a print. Bromide is released into the developer as it is used and so the amount of fog produced should become less and not more.

First, try some new developer and post your results.

All true, but a lack of active restrainer in an active developer will cause fog.

 

[Gerald Koch]

I have seen Kbr oxidize in the jar. I have never found the reson for the contamination, but i have had it happen on at least 3 occiasions over the years.

From someone with degrees in chemistry, please accept the fact that potassium bromide is not going to oxidize when exposed to air. It will not happen. I don't know what you saw but it was not oxidation! The amount of bromide in a developer is not going to mysteriously disappear either. As paper is developed more bromide is released into the developer.

 

[don sigl]

With respect to your degrees in chemistry:
I am aware of the fact that the amount of bromide increases in the developer as it reduces Ag (Agbr). My point was a simple one: If the developer is fogging the paper, you could add a little restrainer to alleviate the problem. As far as bromide not oxidizing: I have witnessed KBr turn brown in the jar. If it was not oxidized, It was contaminated. In fact, I still have some sitting in my lab. I probably should have used the term "Contaminated" instead of oxidized. Regardless, the compound was affected by another compound.
I don't know what could have affected the developer, but I read that the solution was fogging the paper.
My suggestion was valid and is worth testing:
1. Take the remaining developer in question:
2. pour out half into a separate container
3. Add a little KBr to one of the developer solutions
4. expose two test strips.
5. Process each strip in each of the two solutions
6. compare the results.

If the solution with the additional KBr reduced the general fog to an acceptable level, then my suggestion to add restrainer makes sense.

I'm sure you know more about the chemistry than I. But I have been mixing my own photochemistry for 15 years. I never said that a paper developer doesn't increase the level of bromide as it exhausts. And I don't have enough information to know what happened to the develpoper in question, but the first thing I would have done in the same situation was add restrainer. if it didn't work, I would pour it out and start over.

 

[kwmullet]

Here's another idea.

Does your darkroom have florescent lights for the white overhead lights? Florescent lights emit fogging but not visible to the naked eye light/radiation for a bit after power is turned off to them. If you do have florescents, try taking an incandescent lamp into the darkroom and using that for your white light and seeing if it makes a difference. Of course, you'd have to check a sheet of paper from the middle of the stack if your lighting fogged your paper.

If fogging is uniform throughout the sheets, I'm inclined to agree that it's a chemical thing. If it is darkest around the edges and fades toward the center, then I'm inclined to think it's a light thing.

Apologies if all this has already been said. I just skimmed the thread up to this point after the first few messages.

-KwM-

 

[Gerald Koch]

I probably should have used the term "Contaminated" instead of oxidized.

Yes, "contaminated" is a better term. My problem with "oxidized" is that things like this get spread throughout the web and taken as fact.

BTW, I have been mixing my own photo solutions for more than 50 years. When I first started, photo stores stocked chemicals for those who wished to mix their own.

 

[max_ebb]

Since you said the developer turned a muddy dark grey color, my guess would be contamination. Do you pour stop bath into the tray with it sitting next to the developer? Any chance you might have accidentally splashed a little bit of stop bath into the developer when you were pouring it into the tray? Did you do any test strips before the first fogged print? Any chance some stop or fix accidentally dripped into the develper from a test strip?

 

[pesphoto]

hmmmm.... the stop is right next to the developer, but Im usually pretty careful when mixing. I suppose anything is possible. I need to get in there and start from scratch.