Shelf life of raw chemicals

reggie · Sep 29, 2007

Hi:

I have a lot of chemicals that are quite old, 15 years at least. For example, metol, hydroquinone, sodium sulfite, sodium bisulfate. They are stored in their original plastic containers (many are from PF). Does anyone know if these have a shelf-life? I know that properly stored Amidol will last for decades, but I don't know about these other chemicals.

I need to mix some developers and I'd like to use these chemicals if at all possible.

Thanks.

-R

jim appleyard · Sep 29, 2007

Some may be good, others not. Sorry to be so non-specific, but the only way to find out is to test. You may be able to use them as part of paper devs, but be careful in using them as film devs.

Sparky · Sep 30, 2007

There's no reason to assume - with such simple and stable compounds, that they would have changed - unless there has been massive UV exposure (or some other energy source) with chems in their dry state. A great clue as to their health would be their smell (compared to 'fresh').

dpurdy · Sep 30, 2007

I am using some metol older than that and has turned darkish. Not dark like instant coffee, but sort of tan. It works just fine. Seems full strength to me. I had an antique jar of Hydroquinone that was dark as well and it worked fine too.

reggie · Sep 30, 2007

dpurdy said:
I am using some metol older than that and has turned darkish. Not dark like instant coffee, but sort of tan. It works just fine. Seems full strength to me. I had an antique jar of Hydroquinone that was dark as well and it worked fine too.

Awesome. I know some of my developing agents have darkened. Did you use them on paper or film? I'm planning on developing ortho film with the formula.

-R

Mick Fagan · Sep 30, 2007

I also have some quite old chemicals.

Today as I was mixing up some D76, I noted that I will shortly be out of one or two items in the next six months.

My Metol is also a tan colour, I know that I bought it in 1989 and opened it in 1991. As one uses minimal amounts of this particular chemical, I have had it open and have been using it for 16 years now.

This evening I developed two 4x5 sheets of Tmax 100, which has a use by date of 1993. The negs are singing to me, so I am very happy

Mick.

Photo Engineer · Sep 30, 2007

Bad HQ begins to get dark brown and sometimes starts to get a greenish cast to it.

Dry organic chemicals seem to keep rather well in well sealed glass bottles in the dark.

Any chemical that is caking should be suspect until it is tested.

PE

Shelf life of raw chemicals

reggie

jim appleyard

Sparky

dpurdy

reggie

Mick Fagan

Photo Engineer

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