Effects of using Benzatriazole on fogged paper.

naaldvoerder · Oct 29, 2016

I am trying to rescue some paper by adding Benzotriazole to the developer. Can you tell me what the "side effects" will be? Influence on contrast, printing time and developing time. Upto which volume of a 1% solution in 1 liter of developer will be worth trying? I am using Ilford PQ universal. Would it be advantageous to use another developer? Thanks.

bernard_L · Oct 29, 2016

developing time

Induction time (time for first signs of image appearing in dev) will definitely be longer. Total dev time I'm not sure. Make sure you develop fully. Prepare a few identical test strips, develop normal time; norm+30s; norm+60s... Stop when nothing increased dev time brings no change.

Upto which volume of a 1% solution in 1 liter of developer will be worth trying?

I have in a corner of my memory 0.3g/litre for BTAZ as "normal" usage. That is 30cc/litre from a 1% solution.

Influence on contrast

BTAZ helps with fog. Old paper also loses contrast, a different issue. I've tried some reputedly high contrast developers (Dokumol, ID-14) and could not substantiate the claims made by the proponents; at least not with Ilford MGIV paper.

pdeeh · Oct 29, 2016

this is one of those questions best answered by
trying it.
start with 3-5ml of a 0.1% solution per litre of developer and see how it goes

Gerald C Koch · Oct 29, 2016

Slightly fogged paper can be salvaged with either 1% benzotriazole or 10% potassium bromide. More serious fogging is another matter. Development times will be longer with some loss of contrast and change in image tone.

newcan1 · Oct 29, 2016

I have had MUCH better success using a weak ferri bleach to bleach back after dev/fix than I have had with benzotriazole.

piu58 · Oct 30, 2016

BTAZ works fine, but gives a remarkably cooler image. I used it with very heavy fogget paper from around 1940 (!). But there I had to put all darkroom tricks in to get something valuabe: High concentration of BTAZ, very long exposure time and very short developpng time.

Pat Erson · Oct 30, 2016

piu58 said:
very short developping time.

Do you mean like 30 seconds?

Rudeofus · Oct 31, 2016

When I used outdated paper, my problems were not so much fog, but strong decrease in paper contrast, as in "exposing this paper in gradation 4 would give me the same image as exposing fresh paper with gradation 1". Whatever you do with KBr and/or Benzotriazole, make sure you have negs with plenty of contrast ...

bernard_L · Oct 31, 2016

pdeeh said:
start with 3-5ml of a 0.1% solution per litre of developer

???
0.1% solution = 1 g / liter of solution
5 ml = 5/1000 of one liter of the solution contains 5/1000 of 1 g of BTAZ.
added "per litre of developer" we now have 5/1000g = 5mg of BTAZ per litre of developer

See, e.g.: (there was a url link here which no longer exists)
"About 0.2 grams of Benzotriazole per liter of developer is a good starting point." That is 200mg / litre of working developer. Not far from my suggestion above of 0.3g/liter

David Vestal, in The Craft of Photography (recommended) suggests (for 1 litre of developer) 60cc of 2% solution of BTAZ. Each cc of the 2% solution contains (2/100)g of BTAZ, the 60cc amounts to 1.2g of BTAZ per litre of developer.

So, it looks like 0.200...1.2g/litre is the ballpark.

pdeeh · Oct 31, 2016

OK a misplaced decimal point doesn't need a hysterical response.
calm down ffs

bernard_L · Oct 31, 2016

pdeeh said:
hysterical response

???
Is that what your banker told you when you found your balance x0.001 ?

Rich Ullsmith · Nov 1, 2016

As to OP questions. Put a little drizzle of the 1% solution in the tray, and if that doesn't work then drizzle a little more. If that doesn't work, maybe more. But now maybe there is too much, so dilute it with some water, but now development times are getting really, really long. So maybe add more developer. How much? Hm, I dunno. Whatsa "normal" print supposed to look like with this paper, anyhow?

Fogged paper is fogged paper. No magic potion will change that fact. Lith it, make photograms, or toss it. Life is short.

Molli · Nov 1, 2016

Admittedly the attached file gives no indication of the paper's contrast decline through aging, nor does it tell anyone how much, if any, exposure and/or development increase may be required, but I hope it gives a practical example of the reduction in fog possible through the use of Benzotriazole:

naaldvoerder · Nov 1, 2016

Thanks Molli! That is a informative post. Thanks for the effort. Do I read correctly, 7,5 resp. 10ml of a 2% solution? I assume in 1 liter of developer?

Slixtiesix · Nov 2, 2016

Thank´s, that is very illustrative! The Dmax is not affected?

Michael Guzzi · Nov 2, 2016

Quite a newbie question, but does Benzotriazole work the same with all developer agents? Metol, Sodium ascorbate/Ascorbic acid, Phenidone, Hydroquinone etc?

DREW WILEY · Nov 2, 2016

It's not a developing agent, but classified as a "restrainer", a different kind of ingredient.

MattKing · Nov 2, 2016

Michael Guzzi said:
Quite a newbie question, but does Benzotriazole work the same with all developer agents? Metol, Sodium ascorbate/Ascorbic acid, Phenidone, Hydroquinone etc?

DREW WILEY said:
It's not a developing agent, but classified as a "restrainer", a different kind of ingredient.

If I understand Michael's (very interesting) question correctly, he is asking if the behavior of Benzotriazole as a restrainer varies depending on what developing agents are present in the developer you are using.

Michael Guzzi · Nov 3, 2016

Yes that's what I meant, thanks for clarifying my question Matt. Was not sure how to put it.

DREW WILEY · Nov 3, 2016

Compared to KBr as a restrainer, Benz tends to slow print emulsion speed, you need less of it (typically about 1/4 comparable gram wt), and it is more likely to induce a color shift in papers toward cool. Of course, you can combine these restrainers. The practical effect does have a lot to do with
the final image color you are trying to achieve. Many MQ developers can create an annoying "dektolish" greenish tinge in color and neutral tone papers. This might be shifted to a slightly more neutral black by use of benzotriazole. Or maybe not. In Polygrade V, I could achieve an almost blue
black. I am not the correct person to describe what happens chemically. But in practical terms, the whole question is complex enough that the only
really easy answer is simply to experiment. Every time a favorite paper disappears and I need to find a substitute, I'll tinker with several formulas
until I understand what I like or don't like visually. That's what counts. Nowadays I tend to avoid MQ developers in general and stick pretty much to
tweaks of amidol and glycin. But which restrainer I use, and how much, is decided by the end result, including any potential selenium, gold, and sulfide toning, which in every case is matched to the specific image I am working on. Maybe some darkroom workers follow a methodology of "one
shoe fits all" when it comes to developers, but I am not one of them.

darkroommike · Nov 3, 2016

I picked up a pretty old box of Mitsubishi Gekko MC RC, and it's definitely fogged, somewhat more on the top and bottom sheets than in the middle, I really liked this stuff so I'm going to play with both KBr and Benzo restrainers, one other trick I've read about is using Sodium Carbonate to boost developer activity when using KBr, so fun and more fun...

Pat Erson · Nov 4, 2016

Molli said:
Admittedly the attached file gives no indication of the paper's contrast decline through aging, nor does it tell anyone how much, if any, exposure and/or development increase may be required, but I hope it gives a practical example of the reduction in fog possible through the use of Benzotriazole:

View attachment 166431

7.5 or 10ml, is it per liter of developer in the tray?

Molli · Nov 6, 2016

My apologies for not getting back to this far sooner to decipher my scribble for you. Yes, that's 7.5ml of a 2% Solution of Benzotriazole per litre of developer used on the middle strip and 10ml of the 2% Solution used on the right hand strip. I usually start with just a couple of millilitres and add more in small increments.

With regard to contrast, I've hunted through my notes and test strips but don't have before and after prints to show. I'll try to remember to do some more next darkroom session.

As to adding Sodium Carbonate to increase developer activity/deepen blacks, I also read this "trick" some time ago. The paper I tested it on, however, showed no appreciable difference but, then, it may well have been too far gone. Also, my chosen negative wasn't exactly rich in dark tones to begin so I'll dig up a contrastier negative to play with and try a few different papers to see if the sodium carbonate really does help in this respect.

As others have said, it really is a case of try it and see. The main variable is how the paper has been stored. Also, whether the paper was made before or after cadmium and the like seemed like a really good idea!

Gerald C Koch · Nov 6, 2016

Michael Guzzi said:
Quite a newbie question, but does Benzotriazole work the same with all developer agents? Metol, Sodium ascorbate/Ascorbic acid, Phenidone, Hydroquinone etc?

The mechanism is the same however in general developing agents can be said to vary in sensitivity to specific restrainers. Restrainers like benzotrizole and bromide work by being adsorbed on the silver halide crystals. Here they partially block the action of development. The exact mechanism is quite complex and any explanation too lengthy for APUG. For example, are the RA (restraining agent) and developing agent both charged. Here simple electrostatics are involved. Another consideration is how tightly is the RA is bound to the AgX crystal lattice. In other words just how much force is required to dislodge the RA and allow the developing agent access to an active site. For bromide you can find tables for the bromide potential which ranks developing agents in sensitivity to bromide. Unfortunately I have not seen anything similar for benzotriazole.

cliveh · Nov 6, 2016

naaldvoerder said:
I am trying to rescue some paper by adding Benzotriazole to the developer. Can you tell me what the "side effects" will be? Influence on contrast, printing time and developing time. Upto which volume of a 1% solution in 1 liter of developer will be worth trying? I am using Ilford PQ universal. Would it be advantageous to use another developer? Thanks.

If your paper is fogged, Benzotriazole will not rescue it, but just help to stabilise the damage done.

Effects of using Benzatriazole on fogged paper.

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