Old potassium dichromate

mark · Jan 21, 2012

I found 100g of Potassium Dichromate at the bottom of a box at the bottom of a pallet I bought at a school auction this morning. I would say it from the late 80s or early nineties.

Would it still be good?

There was also a lot of glass plates for holograms that said open under safe lights that were wide open. Those are shot. Anyone want some little glass plates?

Hexavalent · Jan 21, 2012

If it's still bright orange crystals, it's likely good. I had a jar on the shelf for 20+ years that was perfectly okay.

John Austin · Jan 21, 2012

If it is still sealed

If it is still sealed and as it was kept in the dark I can see no great chance that it will not be good - However, there is only one real test . . .

mark · Jan 21, 2012

It is pink in color. Does that mean it is bad?

cliveh · Jan 21, 2012

Potassium dichromate is a nasty chemical (handle with care and read the health and safety instructions).

railwayman3 · Jan 21, 2012

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mark said:
It is pink in color. Does that mean it is bad?

Most references describe pot dichromate as being a bright orange-red color, which is how I would describe the product which I've used in the past.

You really need a fresh sample to compare, as we all have different ideas of describing colors. But I wouldn't expect a "good" sample to be a "baby-pink" or similar shade of color?

Hexavalent · Jan 21, 2012

http://en.wikipedia.org/wiki/Potassium_dichromate
The colour shown on Wikipedia is fairly close to 'reality' (at least with my monitor).

johnielvis · Jan 21, 2012

100 grams...pink??? maybe it's just LABELLED at pot dichromate...even diluted with water i'ts always orange...VERY diluted it gets yellow----never heard of pink with this stuff....

well--jsut mix up like 2 grams with some diluted sulphuric acid and see if it will clear a developed negative to cleaar film base..if so..it's what it says it is and it's good

Hexavalent · Jan 21, 2012

Please don't go adding sulphuric acid to things unless you are 110% certain of what you're dealing with.

mark · Jan 21, 2012

I will look at it again tomorrow. It was in a milk white bottle.

I ain't mixing a thing with sulfuric acid unless I am dead sure what it is. I've seen a guy after a chemical mishap.

OzJohn · Jan 22, 2012

I have a small brown bottle of it that would be close to 50 years old and the crystals are still orange. OzJohn

mark · Jan 23, 2012

I opened the bottle and it seems to be the right color. I guess I am good to go.

Old potassium dichromate

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