Benzotriazole Shelf Life?

[John Layton]

I've had a couple of liters of Zone-VI Benzotriazole sitting on my darkroom shelf since...well...since Zone VI was still in business - so maybe 25 years? Richard?

At any rate...I'm anticipating needing a bit of this for an upcoming processing run involving some older paper, and would like to know if the old benzo might still be ok. Looks clear and I'm thinking its a go.

Yeah...I know..."run some tests." But I'm feeling a bit lazy for this. Anyone?

[eric black]

From a chemistry point of view (at least thats what my degree implies)- degrades with UV light and acidic conditions. If it has been exposed to neither (and I would include high temperatures as well) it should still be good. Its also a great antimicrobial so theres that too- it shouldnt get moldy!

[Kevin Crisp]

I have a couple bottles of the Zone VI mix. It has worked fine when I used it for many years after I bought it, but I haven't used any in the last couple years. It could be 20 years old. With I still had some of Fred's paper, that was great stuff.