Quote Originally Posted by j_landecker
Hi everyone...heh, my first post here after much lurking...


So what happened to my Pyrocat? One possibility that occurred to me is that the phenidone in the part A has conked out. If I've got the concept right, phenidone is usually superadditive with a second developing agent in a developer, in this case catechol. My negatives still show a brown stain, implying that the catechol is still doing some work, but without the kick of the phenidone, it's only active enough to develop the highlights. Since I mixed the stock solutions using spoon measurements, I'm wondering if I had too little phenidone...enough for the developer to work for a while, but too little to resist decay in the slowly emtying glass bottle. Come to think of it, the diluted solution doesn't have the pinkish or tan color it may have had originally....but I'm not sure.

Jim
If the developer was working fine when you first mixed it I believe you should discard the theory that there was too little phenidone. The amount you need anyway is miniscule and in my experience it would not go bad in two months in a partially full bottle.

The two most likely reasons why the developer may have failed, in mind would be.

1. Somehow either one or both of the stock solutions was contaminated.

or

2. You failed to add the B solution when mixing the working solution, or the B solution is mislabeled and contains something other than potassium carbonate at the necessary strength.

The very thin negatives that you describe would in fact be what one would expect from using a very weak Stock B solution. This is the accelerator part of the developer that increases the working solution to the pH needed for development, and without it the catechol and phenidone will just sit there and do nothing.

Next time you mix a working solution check the pH if you the means to do so. It should be around pH 10.9 or so.