How to mix Benzotriazole

Hello David,

While APUG was down I was busy in the dark - see my tests below.
I now understand how to do it I think and also the 50%, I think my papers are doing really good actually!

This is my old paper stash:



I've selected 6 of these for the test as I had 6 coins available in my wallet that evening. I tore small pieces off the corners of the sheets and placed them on my workbench with a coin on top of them.



Light went on for 10 seconds (so I could take a quick photo) and then off.

After development this was the outcome:



As you can see the coins weren't heavy enough for some of the paper and as they curled light got underneath. Still even with light penetrating here and there, I can see that the papers aren't that fogged actually.

This brought me great confusion as I now don't understand how come some of the papers under perform.

Question of the day:

Is Fog and Loss of contrast unrelated? Can it be that my papers have lost the contrast but aren't actually fogged?

I am sure they are fogged to some extent as I remember enlarging a large 20x24 image of a sailboat whose sail ended up being gray-white rather than white as it showed on smaller prints I did with new paper.

Anyways - the paper is definitely not terribly fogged and with the BZAT I managed to print with good results.

Another thing. Low and behold - back to my Original Post - the BZAT broke down again. Seems like it keeps in solution for about a week and then breaks down. Could it be the cold?

See what I found when I opened the bottle to use it for a fresh batch of developer.
Sort of a shocking sight when I expect a normal transparent solution.



Thanks,
Ben

The papers are NOT particularly fogged. I cannot answer why the contrast is not as it should be: loss of contrast is a function of age-fogging. All you should have to do with these very slightly fogged papers is to develop normally and not worry about any fog, since a short time in Farmer's Reducer (diluted much, so that you will not have trouble stopping in time) to clear off the highlights. Remember to make certain that your prints are slightly darker than normal so that you will not end up with a print that is unduly light.

In solution, I never have had a problem with the BZ going BACK into its original form.

- David Lyga

Thank you David - I'll test the farmer's reducer in the next few days and report back with what I managed.

Glad to hear you also feel my paper isn't particularly fogged!
Have a nice day,
Ben

Photo Engineer said:

Do not use denatured alcohol, as the denaturant can be harmful to photographic processes.

Do use alcohol, iso propyl alcohol or other water miscible organic solvents. I usually use 1% in DW though.

PE

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I know this is really old thread but I am having this issue that my 2% benzo solution is not stable, it gets hairy. So next I am planning to mix it with alcohol but can I use glycol as it will make the oxidation nearly zero? Or glycol is a denatured alcohol and is not suggested. Thank you

Faith,

Just mix a 1% solution then and use twice as much.

Distilled water, if you're not using it, might help. A 2% solution is really close to saturated and those "hairy" crystals will start on impurities or irregularities in the container or on dried out starter crystals around the lid of the bottle. A 1% solution reduces this quite a bit.

Best,

Doremus

Doremus Scudder said:

Faith,

Just mix a 1% solution then and use twice as much.

Distilled water, if you're not using it, might help. A 2% solution is really close to saturated and those "hairy" crystals will start on impurities or irregularities in the container or on dried out starter crystals around the lid of the bottle. A 1% solution reduces this quite a bit.

Best,

Doremus

Click to expand...

Thank you so much, that seems to work. Although time to time it crystalize again, then it gets back to its fully liquid form. Maybe it is temperature dependent as well.

Fatih Ayoglu said:

So next I am planning to mix it with alcohol but can I use glycol as it will make the oxidation nearly zero?

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I don't think benzo oxidizes.

I've never had any of the 1% solutions I've mixed go cloudy. They've been stored at room temperature that has never been below ~17 degrees (about as cold as it gets in there in the winter).

Fatih Ayoglu said:

Maybe it is temperature dependent as well.

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Solubility is very dependent on temperature indeed, so it's plausible that a 1% benzotriazole solution in water might crystallize at low temperatures. It's common for solubility rates to be given for T=20C.

I mix BZT in alcohol. Dissolves readily, unlike in water and doesn't come out of solution even at 10%. I use 90% isopropanol.

A pinch of S. Carbonate in the water will help it dissolve if that's the way you want to go.

Nicholas' solution (no pun intended) sounds like it's the best way to go. I don't think benzo goes bad, so you could probably mix it once and never have to mix it again.

I also prefer to keep it in an alcohol (ethanol) solution. Dissolves easily, keeps well. The only drawback I can imagine is that if the container doesn't seal properly, the alcohol will evaporate, resulting in an ever increasing concentration of benzotriazole until the solubility limit is reached. However, in a properly sealing bottle, this is not an issue.