Fenton test results
The Fenton test consisted of adding Fe and Cu ions (iron and copper) to the developer to simulate iron and copper pipes, and impurities in chemicals. I added 1 mg/L each of Fe(II) and Fe(III) ions using ferrous sulfate heptahydrate and ferric ammonium sulfate, and 2 mg/L of Cu(II) ions by adding copper sulfate pentahydrate. Jerry: I used ferrous sulfate because PhotoFormulary doesn't carry ferrous ammonium sulfate. Was this change a mistake? The separate beaker of these ions at 100x concentration was a cloudy light-yellow. Surprise: When adding 1 ml of it to the developer, the developer turned light purple. I'll guess the ammonia is reacting with something.
Originally Posted by Alan Johnson
I waited 50 minutes before developing, to simulate easy-going one-shot usage. Here are density-curves with and without these added ions:
The curves match well, so the Fenton reaction had no measurable effect. Nor did the purple, fortunately.
Earlier tests show that hard water causes cloudiness starting at 30-45 minutes after mixing. So all should go well if this one-shot is used within 30 minutes of mixing.
I guess my next step is to mix the concentrate and test its longevity and compatibility with various films. Comments are welcome as always.