Bulk chemistry ingredients - keeping properties? (How old is too old?)

[PhotoJim]

Hi,

I have a pretty good stash of bulk chemical ingredients that I got many years ago (some as long ago as fifteen years). I fell out of darkroom work for several years and now I'm starting to get back into things, and I'm wondering what can stay and what should go.

I'm particularly concerned about developing agents (I have hydroquinone, metol, and Phenidone, plus pyrogallol and pyrocatechin) plus the other standard things you'd expect - potassium bromide, borax, sodium carbonate and sulfite, and so on. I can make a full inventory if it would be helpful.

I'm not sure off the top of my head which form of the chemicals that come in various -hydrate forms are, but I'm sure they're properly labelled and I realize the full-water and monohydrated versions will have tended to have reverted to the stable form.

Are the developing agents okay? Or at least, likely enough to be okay that it's worth mixing up a developer and testing with an unimportant roll? What about the other ingredients?

Thanks in advance!

Jim

 

[Donald Qualls]

I have a metol sample that was twenty-some years old when I received it (for comparison to my main stash, then freshly purchased). Now, it's 35 years old, stored in a 35mm film can. It's still barely off white.

Clumping is the big red flag for some chemicals (sodium carbonate, sodium thiosulfate, sodium carbonate, etc.). The chemical is still good, but it's a major PITA to use when there's a clump as big as your fist and as hard as a rock instead of granules you can portion out with a spoon.

I can tell you that my CD-4 did not survive twelve years in the jar it came in, with five of those years in uncontrolled conditions in a shed (well below freezing in winter, above 100F in summer). I'm pretty sure, now, that I don't trust my CD-3, either, nor the little bit of glycin I have in there. The metol and phenidone are fine, the hydroquinone most likely as well. I'd have to open the ascorbic acid to be sure.

 

[koraks]

Out of that list, only the pyrogallol would be doubtful, but may be ok still. The rest is most likely just fine if it was stored dry.

 

[Alan9940]

I have metol, hydroquinone, pyrogallol and pyrocatechin that are all many years old and I've never noticed any issues. For some raw chemicals, you can tell if they've gone off by their color. Hydroquinone, for example, should be a near white powder; if it's tan/brown, it's bad. KBr, borax, carbonates, etc, will last a long time, even in no so ideal storage conditions. As Donald points out, clumping can be an issue, though it doesn't mean the chemical is bad. When I get clumps, I put them in a clean, heavy duty ziplock bag, then use a rubber mallet to gently break them up. I don't try to pulverize the clump, just return the chemical to more useful (and dissolvable) size. A new clean bag is used for each different chemical.

 

[PhotoJim]

I like the hammering idea. I didn't have a lot of sodium carbonate, but I do have some, and I know I have a pretty good bucket full of sodium sulfite that hopefully hasn't absorbed too much water.

I haven't looked at most of my developing agents yet, but my pyrocatechin looks brownish-grey. I forget what it looked like new.

Sounds like I might be okay! I appreciate the responses.

Probably one of the best things I could do first would be to mix up some print developer instead of film developer.

 

[PhotoJim]

Oh, forgot to mention - the darkroom tends to wobble between 10-18 C depending on the time of year. It's in a heated basement (at my mother-in-law's house; I shared it with my father-in-law until he passed, and then my mother-in-law told me not to be silly and to just keep using it instead of building my own). Most of the chemicals are in opaque containers, but the darkroom would have been dark almost all the time.

 

[john_s]

Ian Grant has reported that sodium metabisulphite deteriorates and if old, can cause Pyrocat-HD, the original version in water, to not last well.

 

[PhotoJim]

Ian Grant has reported that sodium metabisulphite deteriorates and if old, can cause Pyrocat-HD, the original version in water, to not last well.

I likely have some. I did make a batch of Pyrocat HD once. Thanks for the tip.