Benzotriazole (BZT) use in defogging bromide papers

I've seen reference to people using BZT as an addition in their developer to help control fogging in bromide papers. I've seen "add a pinch", "add a little", "add some"... but nothing exact.
Can anyone recommend an exact quantity to use (or at least to start out) with PF's 130 Devloper? I've got some old Brovira paper I would like to try to print on this weekend, but I don't have much of it so I would like to minimize waste in testing.
Your thoughts are appreciated, but your shared experience would be better.

Thanks,
Chris

When I was printing in the darkroom with Ansco 130, I kept a one liter bottle of 2% BTZ solution on the shelf.

I would add 25ml of the 2% solution to an 11x14 tray, or 50ml to a 16x20 tray of developer whenever needed.

Kodak used to sell BTZ in tablet form, they called it "Anti-Fog". Had to wait for a tablet to dissolve in the developer.

Works faster when made up as a 1%, or 2% solution. Has a long shelf life

I add 1/2 gram of benz powder per liter of stock 130 developer, prior to working tray dilution. But this is done by substituting for KBr, which is itself a restrainer. The result is
a slightly colder tone. If you use both restrainers together you might need to reduce the
amt of KBr. It is a little easier to premix a 1% solution of benz and store it in a bottle.
Then add 20ml of 1% benz per liter of 130 stock prior to dilution.

I have kept a bottle of 2% on the shelf over the sink for many years. I add 20-50 ml to a liter as needed.

Quote:

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Originally Posted by Jim Noel

I have kept a bottle of 2% on the shelf over the sink for many years. I add 20-50 ml to a liter as needed.

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This is precisely what I do, but rarely to prevent fog on old paper; I use it to clear whites a bit and give the print more snap.

You could use the upper amount as a starting point, develop a test strip (exposed to a middle value with a white border) and then see how the fog is. If needed, add more BTZ, in 25ml / liter amounts. However, you can only do this twice or three times more before you kill your developer.

Another way to deal with fog, and one I have used successfully with fogged paper, is to use a weak solution of potassium ferricyanide / potassium bromide bleach. If you immerse the entire print, the highlights will bleach back faster than the other areas. This is often quite gratifying. I imagine you could use a weak solution of Farmer's Reducer as well. The trick is to keep an unbleached print available for comparison as well as a strip of max white to compare the borders of your bleaching print to. Pull it shortly before the white of the bleached print is max white or when any of the lighter grays and mid tones start to show some unwanted bleaching.

If your paper is really fogged, it helps sometime to print a darker and let the bleach work on the entire print a bit longer. If you print just dark enough, the other tones will arrive where you want them just as the whites clear.

Or, you could buy new paper...

Hope this helps,

Doremus

Thank you for all of your input.
I will put it to task and see how it works.

For many years I used Na or K Bromide in a salt shaker for that purpose. It worked a heck of a lot better than BZT. Give it a little shake and try it! I don't know if you can get bromides easily any more, however it is a powerful cerebral depressant so don't leave it around kids or idiots, it can kill you!

Lynn

Quote:

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Originally Posted by Jim Noel

I have kept a bottle of 2% on the shelf over the sink for many years. I add 20-50 ml to a liter as needed.

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2% or 0.2%? I ask because I've seen references to making a "0.2%" solution.

Quote:

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Originally Posted by HMG

2% or 0.2%? I ask because I've seen references to making a "0.2%" solution.

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2.0%

A friend and I discovered fog on brand new paper. We each cut a piece of 8x10 into pieces, tossed a piece into fixer, developed and fixed another piece. Voila! the developed piece showed fog! I use about a liter and a half of print developer in 10x12 trays. I added about 25ml of 2% solution of BZT at a time, repeating the test until there was no more fog.

So, with one paper tested, I wondered about other papers I had. Repeated. Yup, all showed a little fog, cheap RC bought for proofing showed a lot, even though brand new, and some older ones more than a little. Worked out how much for each, wrote it down and taped it to the wall. Good enough.

Richard Ritter then weighed in: "Of course there's fog. That's why all the really good printers use BZT routinely." I do, now, and my whites are whiter. My prints are cooler, and therefore so am I.

Bruce,
When you did your test, were the safelights off? If so this is an important piece of info. Something I have never considered.

Safelights on. I had tested them long ago, and found them true to their name. And yes, anal testers, I had flashed the paper to break the exposure threshold.