Keeping solutions of KBr and Benzotriazole

Jarin Blaschke · Jul 15, 2017

Hi all:

Do I need to add any Sodium Sulfite or other preservative to a bottle of 10% Potassium Bromide and a bottle of 1% Benzotriazole that I'm making up today? Or just restrainer and water only? How long can I expect these to be reliable? -years?

Thanks!

-Jarin

Photo Engineer · Jul 15, 2017

Nothing need be added. They both keep well for a year or so. Use distilled water.

PE

Jarin Blaschke · Jul 15, 2017

Thanks!

Jarin Blaschke · Jul 15, 2017

In solid form, how long do Benzo. and KBr last? I have Benzotriazole I bought in May 2015.

Photo Engineer · Jul 15, 2017

Benzotriazole is fine, and KBr will keep for years as well. As long as both are free flowing, you are fine.

PE

Jarin Blaschke · Jul 15, 2017

Thanks. Free flowing?

Photo Engineer · Jul 15, 2017

Yes, not clumped or brownish. Free flowing crystals or powder that are both white or just slightly off white.

PE

Pat Erson · Jul 15, 2017

Photo Engineer said:
They both keep well for a year or so. Use distilled water.

PE

Only one year PE? I intended to use some Benzo I diluted years ago (in alcohol...). Me worried now.

Ian Grant · Jul 15, 2017

Pat Erson said:
Only one year PE? I intended to use some Benzo I diluted years ago (in alcohol...). Me worried now.

Both keep years, Benzotriazole should be in a Sodium Carbonate solution. 10g Benzotriazole, 10g Sodium Carbonate, water (distilled or de-ionised) to 1 litre.

Ian

Pat Erson · Jul 15, 2017

Thx Ian!
"a Sodium Carbonate solution"? Whoops... I foolishly "dumped" 100g of Benzo in a liter of alcohol. Live and learn.

bernard_L · Jul 15, 2017

I have my benzotriazole as a 1% solution in diethylene glycol. Made up 3 years ago. Can I expect it to be still OK? How should I check?

Jarin Blaschke · Jul 15, 2017

My KBr is white, but includes some giant crystals, some 3/4" long. Presumably ok? The Benzo is still like cotton.

Photo Engineer · Jul 15, 2017

Pat Erson said:
Thx Ian!
"a Sodium Carbonate solution"? Whoops... I foolishly "dumped" 100g of Benzo in a liter of alcohol. Live and learn.

See my post above. I said YEARS! And you don't need Sodium Carbonate. Alcohol will do!

PE

Pat Erson · Jul 16, 2017

Photo Engineer said:
you don't need Sodium Carbonate. Alcohol will do!

PE

Whoa one of my darkroom practices has been sanctioned by the one and only PE.
I feel like I've won the Hasselblad prize! (minus the 150K $ donation though...)

Ian Grant · Jul 16, 2017

Pat Erson said:
Thx Ian!
"a Sodium Carbonate solution"? Whoops... I foolishly "dumped" 100g of Benzo in a liter of alcohol. Live and learn.

Ilford sold Benzotriazole solution - Ilford IBT Restrainer, 10g Benzotriazole in a 1% Sodium Carbonate solution. There's nothing wrong with dissolving in alcohol, it's not particularly soluable in water only 20g/l @ 20ºC.

Ian

Gerald C Koch · Jul 16, 2017

At one time Kodak sold BZT as little tablets the size of baby aspirin. On the bottle was a chart indicating how may tablets to use per quart. ! tablet for developers like Microdol and two tablets for more active developers like D-72. Very handy as no measuring was required.

Jim Noel · Jul 16, 2017

Gerald C Koch said:
At one time Kodak sold BZT as little tablets the size of baby aspirin. On the bottle was a chart indicating how may tablets to use per quart. ! tablet for developers like Microdol and two tablets for more active developers like D-72. Very handy as no measuring was required.

The tablets must keep forever.I have a couple of bottles I obtained in the 50's and they still work perfectly.

Keeping solutions of KBr and Benzotriazole

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