Shelf life of 1% Pottasium Dichromate?

M Carter · Mar 21, 2020

Anyone know? I was having Bromoil issues and thought it was my 5 year old bottle, got some new and it's the same (real issue was unsuitable paper). But curious, in a sealed bottle out of the light, is it one of those "pretty much forever" chemicals?

Vaughn · Mar 21, 2020

Indefinite storage -- yes...one of those forever chemicals...not even light sensitive, as far as I know. However if contaminated with organic material (gelatin, some sizing, gum arabic, etc) it will go bad.

mohmad khatab · Mar 21, 2020

I recommend a very immersed developer
But it has a completely different flavor
Agfa14

M Carter · Mar 24, 2020

mohmad khatab said:
I recommend a very immersed developer
But it has a completely different flavor
Agfa14

Ummm... for tanning bromoil matrices?

BrianShaw · Mar 24, 2020

Vaughn said:
Indefinite storage -- yes...one of those forever chemicals...not even light sensitive, as far as I know. However if contaminated with organic material (gelatin, some sizing, gum arabic, etc) it will go bad.

I wish I knew that a few weeks ago. I dumped a bottle just because it was dated 1982.

mohmad khatab · Mar 24, 2020

M Carter said:
Ummm... for tanning bromoil matrices?

Development of black and white film

Vaughn · Mar 24, 2020

BrianShaw said:
I wish I knew that a few weeks ago. I dumped a bottle just because it was dated 1982.

I hope you were able to dump it properly. Nasty stuff -- but the hazard can be greatly diminished by treating it with Vit. C (Ascorbic acid).

eli griggs · Mar 24, 2020

Vaughn said:
I hope you were able to dump it properly. Nasty stuff -- but the hazard can be greatly diminished by treating it with Vit. C (Ascorbic acid).

By what ratio or measure?

Vaughn · Mar 24, 2020

Sprinkle it in until it changes color. The Ascorbic acid is pretty cheap.

eli griggs · Mar 24, 2020

Cheers!

M Carter · Mar 25, 2020

mohmad khatab said:
Development of black and white film

if you read my post, I'm discussing using it for tanning bromoils - A B&W film developer isn't going to work for that application.

M Carter · Mar 25, 2020

Vaughn said:
I hope you were able to dump it properly. Nasty stuff -- but the hazard can be greatly diminished by treating it with Vit. C (Ascorbic acid).

I've read that used fixer will work; will any acid do the same thing? I don't have ascorbic, but I have plenty of acid stop. I don't dump the straight stuff, but I do dump the bromoil bleach/tan, which has a few ML of 1% in the solution, depending on tray size.

Andrew O'Neill · Mar 25, 2020

Vaughn said:
I hope you were able to dump it properly. Nasty stuff -- but the hazard can be greatly diminished by treating it with Vit. C (Ascorbic acid).

That's great information. Thank you, Vaughn!

Vaughn · Mar 25, 2020

M Carter said:
I've read that used fixer will work; will any acid do the same thing? I don't have ascorbic, but I have plenty of acid stop. I don't dump the straight stuff, but I do dump the bromoil bleach/tan, which has a few ML of 1% in the solution, depending on tray size.

In carbon printing we'll get some dichromate build up in the transfer bath, and cleaning things up. I just sprinkle it in the tray, stir it up a little and wait for the color change.

Ascorbic acid is cheap and easily bought online or in health food stores. On-line I have seen 5 pounds for $6/lb.

Other chemicals might work -- but this is cheap.

Anon Ymous · Mar 25, 2020

I've never heard that bichromate can be treated with ascorbic acid to convert it to something not carcinogenic. I'm sure sodium sulfite will convert hexavalent chromium to trivalent and this is something most of us have at hand.

Steve Goldstein · Mar 25, 2020

Ascorbic acid converts it from hexavalent to trivalent. That doesn't change the fact that it's a heavy metal, though.

BJ68 · May 27, 2020

M Carter said:
will any acid do the same thing?.

No....you need either fixer-Solution or ascorbic acid....see my posting https://www.photrio.com/forum/threads/dichromate-waste-treatment.135482/#post-1769722
New Link to the paper: https://www.researchgate.net/public...hromium_by_ascorbic_acid_in_aqueous_solutions because the link in the original post does not work anymore...

For example "citric acid" does not work: https://www.photrio.com/forum/threa...er-containing-dichromate.162887/#post-2121668

bj68

Shelf life of 1% Pottasium Dichromate?

Moderator

Privacy & Transparency

Privacy & Transparency