Discussion in 'Darkroom Equipment' started by RAP, Jul 9, 2003.
How do I make up a 10% solution of potasium bromide from a powder? Is it 1 gram/100ml water?
No, 10g/100ml water.
Since 1ml water=1g, 1g/100ml would be 1%.
GOD BLESS PHOTOGRAPHER"S FORMULARY! THEY HAD THE ANSWER!
The reason I was so anxious this afternoon was that I had run out of benzotriazole and the only thing I had as a substitute was potassium bromide, KBr. But I had forgotten what the ratio was for a simple 10% solution. WHAT A DUMMY!
I called Kodak and suffice it to say, they were no help. The rep has not called with the answer as he said he would. He questioned me where I heard of KBr and I said that AA's "The Print" had it listed as an anitfog chemical. He said, "why don't I ask him?" I said that I do not talk with the dead.
I called Calumet and they said they had discontinued the Zone VI bottled benzotriazole, because of the proliferation of the "D" word.
So I called Photographer's Formulary. The girl who answered, the receptionist, knew the answer! Maybe she wasn't the receptionist but I was very very impressed! She had it right on the tip of her tongue.
Suffice it to say, I am a Photographer's Formulary customer from now on!
BTW, they do sell powdered benzotriazole.
The Kodak response is brilliant.
I've been using benzotriazole in place of Kbr for decades.
Does any one remembers Kodak Anti Fog n. 1 in pills?
man, I'm THAT old!
Apparently so am I. I remember the Kodak pills from 20 years ago. I had some but never used them and ended up throwing them away. I used the Zone VI for years but now Calumet discontinued it.
I remember those pills, too, but I never used them myself. I've been using Edwal Liquid Orthazite lately as a restrainer, which is a solution of benzotriazole and sodium sulfite.
I've never used benzotriazole with the amidol formula. From what I understand it will make the prints a colder tone. By increasing the amount of potassium bromide you can warm the print tone. I usually start with 4cc of 10% bromide, and if the prints look too cool (not that kind of cool), I just add more. Hope this helps.
I think that from what I have heard the use of Benzatriazole in the Amidol formula, for use with Azo, has to do with the age and place of manufacture of the Azo paper. Grade two Azo is currently manufactured at the new plant in Canada with a corresponding new emulsion (wouldn't you know this about Kodak...take a good thing and change it). The grade three Azo is also manufactured in Canada with no change in emulsion. Grade two Azo is the paper that some people are incorporating Benzatriazole with the Amidol formulation.
According to Michael Smith, it's not Kodak's fault. There's been a change in the chemistry of the gelatin they can get which forms the substrate of the emulsion. Their choice was to either make the change or stop producing Grade 2 altogether. Personally, I'm rather happy that they chose the former. I've gotten much better prints with it than the old Rochester emulsion.
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