We are open for business and following current LA County DOPH & CDC guidelines. Put on your mask and come on In! We appreciate your support!
**Please note: product listings represent stock availability at our Santa Fe Springs Location & for Shipping. Due to increased shipping demand, Fed-ex, UPS and USPS are reporting longer than normal shipping delivery times. To check stock in our Hollywood Retail Store, please call 323-284-4321.

Precipitate in PMK developer Solution A?

By: Gordon Hutchings

Dear Gordon,

I recently noticed a white precipitate in Solution 'A' of my PMK developer, which is now several years old. I have also noticed a progressive increase in fog in negatives (FP4+) processed in this chemistry.

Is it possible that the precipitate is sodium sulphite and that this is causing the increase in fog density, due to loss of acidity and hence an increase in pH?

Thanks,
Chris

Dear Chris,

Clearly something has gone wrong with the A solution. Don't use it. In over 30 years use, I have never seen a white ppt. in the A solution. My guess is that somehow the bi-sulfite has combined with something to cause it to become an insoluble carbonate compound, I think. If this happens, the pH would be out of control and fogging and oxidation would occur.

Time to buy some new solution.

Yours,
Gordon