Pyrocat MC Longevity

The question about Pyrocat longevity comes up here on a regular basis. Just for info, I used some yesterday which was mixed in Glycol in August of 2012 and has been on my chemical mixing bench in an open squeeze bottle.
Results were perfect, times and results the same as normal. Color change when mixing and clearing were right on time also...in other words...zero deterioration.

Can't comment about MC but I have some Pyrocat HD in water (no Glycol) that's still perfect that I made up in March 2011, it's stored in a part full bottle.

What I've found is that while the Metabisulphite is still giving off SO2 Part A desn't oxidise and keeps well, the secret is using fairly fresh Metabisulphite when mixing the solution.

I've much older Pyrocat HD made up in Glycol in Turkey, I actually made Part A double strength but you have to use a little water to dissolve the Metabisulphite, I did this to cut the weight for flying and then mix 1+1 with water to make a normal stock solution of Part A once there, I source the Potassium Carbonate locally. I'll be using it again in a couple of months but it should be fine.

Ian

Evan,
I have part of a box of Efke 25 2x3 sheet film and was doing a little developer testing a week or so ago using the Efke sheets. I ran it in Pyrocat-HD, Pyrocat-MC, WD2D+, Rodinal, Perceptol and F76+. The Pyrocat-HD(homebrew/glycol) was mixed 2/11/11 and the Pyrocat-MC(homebrew/glycol) was mixed 3/8/12 and both acted exactly like they did when first used. The results of the test were all so close that any of the tested developers would be fine to use. My picks were, in order of preference, WD2D+, Pyrocat-MC, Pyrocat-HD, Rodinal, F76+ and Perceptol. It's easy to see why some people live with just one of the Pyrocat developers and are very happy campers. I certainly could thin my developer shelf out and have nothing left but Pyrocat-MC. Maybe Rodinal when it was needed for a "different" look. I'd then have two very, very long lasting developers. Hmmm, sounds like something I should be thinking about maybe? JW

Thanks. Prompted by all the homebrew Rodinal threads, I simply asked Ian how he would approach it.

Thus came Ianol and it's my favorite for Delta and FP4, it has a great shelf life..

Ianol
p-Aminophenol.(free base) ................... 53 g
Potassium sulphite 45% sol...................... 1L
Potassium Hydroxide ........................... 54 g
Potassium Bromide ............................. 13 g
Benzotriazole 1% ............................... 13 ml
Water to make .................................. 1.3 L

Stock pH 13.2

The goofy, 1.3 L allows one to use an even 1l bottle of 45% Potassium Sulphite solution..one dump.

I get flamed for my method for mixing stock, which is weighing, but it's dead accurate, really simple and requires less glassware cleanup. I use 28g per liter to make the stock solution..

eclarke said:

Thanks. Prompted by all the homebrew Rodinal threads, I simply asked Ian how he would approach it.

Thus came Ianol and it's my favorite for Delta and FP4, it has a great shelf life..

Ianol
p-Aminophenol.(free base) ................... 53 g
Potassium sulphite 45% sol...................... 1L
Potassium Hydroxide ........................... 54 g
Potassium Bromide ............................. 13 g
Benzotriazole 1% ............................... 13 ml
Water to make .................................. 1.3 L

Stock pH 13.2

The goofy, 1.3 L allows one to use an even 1l bottle of 45% Potassium Sulphate solution..one dump.

I get flamed for my method for mixing stock, which is weighing, but it's dead accurate, really simple and requires less glassware cleanup. I use 28g per liter to make the stock solution..

Click to expand...

Evan,
That's Potassium "Sulphite" or "Sulphate", right?

Ach, I'm an old man and can't type That's correct.

The weighing of the chemicals is really good for the MC. I use 1.5+1.5+100 and it's really good for those small amounts, especially when they are made with gooey glycol.

eclarke said:

The weighing of the chemicals is really good for the MC. I use 1.5+1.5+100 and it's really good for those small amounts, especially when they are made with gooey glycol.

Click to expand...

I've been using 1+1.5-2+100 for Pyrocat-MC in glycol, but I use a hypo-syringe with no problem at all. I do keep two separate syringes marked "A" and "B". I learned my lesson about cross-contamination a little while back and don't want to repeat that mistake again. Evan, you're old and can't type and I'm old and can't type or read! JW