Stale Pyrogallol ?

Hello.

I have inherited a few photography chemicals.
One small jar labelled pyrogallol has some hardened white powder that is going black.
I have never seen pyrogallol like that, it has always been a clean white powder with a few clumps in it.

Can anyone confirm that it is past it's usable life?

Is there a simple test to see if it is still viable?

Thank you in advance folks.

My bet is it'll work fine and will be indistinguishable from fresh pyrogallol. You could scrape off the black bits or just discard it altogether if you don't like to run the risk. Personally I'd mix up a developer with it, give it a try and use it if it seems to work OK.

BobUk, unless you can place the lumps very carefully into water the wearing suitable gloves and get them to dissolve, my reading of the danger with pyrogallol is that any attempt to crush the lumps back into powder needs to be done with a mask fitted with filters

The dust is not stuff you want to breath into your lungs

For those who know, is this me being far too cautious? Please say so if it is

pentaxuser

I've no done this myself, but it seems to me that if the chemical is no more difficult to clean-up mixing utensils from than the average use of Dawn and warm water, an inexpensive sonic cleaner with a plastic tank and removable basket should be ideal.

Harbor Freight sells/sold such a small machine and I've seen similar on eBay & Amazon.

Take your water or other, nonflammable, long term liquid solution and nearly fill the cleaner's waiting basin.

After getting an absolute dry weight reading, of the chemical you've got, slowly lower it into the solution, by lowering the measuring paper, aluminum foil or scale's measuring basket.

Move the chemical slowly off the support, remove support for washing or trash, putting it in an open baggie in a larger trash bag for disposal.

Close the lid of the sonic cleaner, seal it's top with electrical tape or good vinyl duck tape and turn on the machine as often as needed to break up the lumps and dissolve it all.

Leave it for a day or three, then, unseal and decant the basin, and put into a plastic bag for moving to the place where you can safely wash it out.

Now, you can workout the made solution ratio and come up with a standard volume of the mixed solutions with which you can mix up your developer, as usual.

If you need gloves, I recommend the 9ml black nitrile gloves Harbor Freight sells; throw the used ones away as needed.

IMO, this should work well & safely.

pentaxuser said:

The dust is not stuff you want to breath into your lungs

Click to expand...

This is correct. Btw, it's generally true for most developing agents, but stuff like pyrocatechol, pyrogallol, the color developers (to varying degrees) and a number of other things are especially risky due to their carcinogenic nature. I'm not too sure if hydroquinone is all that much safer, btw, since it's chemically very similar to pyrocatechol. For some reason, the 'pyro' developers do have a worse safety reputation than the still omnipresent hydroquinone; I don't know if that's really in line with the risks associated with each of these chemicals.

Anyway, long story short: don't breathe in your developers. A mask is a good idea, but it's best to prevent kicking up dust in the first place. This is not incredibly hard to do, btw. If you carefully spoon small quantities of this stuff, it doesn't really get airborne.