How to mix Benzotriazole

bence8810 · Jan 26, 2016

Hello all,

I bought some BZT from the Photographers Formulary and mixed it up in hot water (circa 80Celsius) and stirred until dissolved.

I have since stored it in a glass jar and when I came back to it today I saw it totally returned to its original crystal like form.

What did I do wrong?

Thanks,
Ben

pdeeh · Jan 26, 2016

how much benzotriazole?
how much water?

JW PHOTO · Jan 26, 2016

bence8810 said:
Hello all,

I bought some BZT from the Photographers Formulary and mixed it up in hot water (circa 80Celsius) and stirred until dissolved.

I have since stored it in a glass jar and when I came back to it today I saw it totally returned to its original crystal like form.

What did I do wrong?

Thanks,
Ben

View attachment 123698

What was your ratio of chemical to water for this mix? I have mixed it for 1% or 2% solutions and never encountered any problem. Even at a 20% solution rate I have never seen this. You must have a very high chemical to water ratio????

bence8810 · Jan 26, 2016

I mixed 2gramms to 100 ml of liquid (filtered water)

Ian Grant · Jan 26, 2016

Ilford IBT Restrainer

Ilford IBT Restrainer - Benzotriazole solution.

Sodium Carbonate (anhyd) 10g
Benzotriazole 10g
Water to 1 litre

You need the carbonate to dissolve and keep the Benzotriazole in solution. This is the solution used in Ilford published formulae.

Ian

bence8810 · Jan 26, 2016

Ian Grant said:
Ilford IBT Restrainer - Benzotriazole solution.

Sodium Carbonate (anhyd) 10g
Benzotriazole 10g
Water to 1 litre

You need the carbonate to dissolve and keep the Benzotriazole in solution. This is the solution used in Ilford published formulae.

Ian

Thank you Ian!
I went with what was written on the plastic container of the chemical and mixed it according to them.
Before throwing the mixed solution I reheated it and now it's dissolved again. I am letting it cool and hope it'll remain in solution.

I'd use this for defogging paper - would your solution work as well?

I'll report back!
Ben

David Lyga · Jan 26, 2016

In a 500 mL capacity bottle, I put 1 gram of BZ and 250mL of water. I cap it and shake vigorously for a few minutes. I never have problems with this solution reverting to crystals. What Ian said about carbonate is interesting but I have never had to do this. - David Lyga

NB23 · Jan 26, 2016

it all dilutes in 100ml rubbing alcohol. Then, add water.

Magic

Gerald C Koch · Jan 26, 2016

Benzotriazole has a limited solubility in water (< 2% w/v at room temperature) and is usually mixed as a 1% solution. Solutions using sodium carbonate as a solubilizing agent should not be used in low alkalinity developers for obvious reasons. The water may be warmed to hasten solution.

Wayne · Jan 26, 2016

Pretty sure I used propylene glycol for my BZAT solution

john_s · Jan 26, 2016

Even a bit of sodium sulphite will help it dissolve, and should be benign for developers.

Photo Engineer · Jan 26, 2016

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

bence8810 · Jan 26, 2016

Hello all,

Thanks for all the help.
The BZAT has stayed as a solution overnight in my kitchen so I guess it did properly dissolve this time.
I capped it and it went back into my darkroom, which is hovering at 12Celsius all winter along. Could that have been the issue, the cold? I'll check it in a few days to see.

I read above Iso Propyl alcohol etc, if I went down that route next time around, how would I use it?
Say I want to make a 2% solution, I'd mix 20g in 100ml of alcohol and then add 900ml of water at the end? Or I'd add the 20g of BZAT to 1liter of isopropyl alcohol straight up?

Another question if I may - this is the developer I use with my expired fiber papers:

How much of the 2% solution you think I should add to a liter?

Forte FD-103

[TABLE="width: 169"]

Metol
[TD="align: right"]1.0[/TD]

Sodium Sulphite
[TD="align: right"]22.0[/TD]

Hydroquinone
[TD="align: right"]4.0[/TD]

Sodium Carbonate
[TD="align: right"]22.0[/TD]

Potassium Bromide
[TD="align: right"]1.0[/TD]

[/TABLE]

Thanks,
Ben

Photo Engineer · Jan 26, 2016

For a 2% solution of BTAZ in alcohol use 2 g BTAZ in 98 g alcohol. This makes 2% wt/wt BTAZ in solvent.

This is true for any mixture regardless of density. That is why weight is better than density.

PE

bence8810 · Jan 26, 2016

Hi PE,

Thanks for that!
If I wanted a liter though could I dilute the 20g BZAT - 80g Alcohol mix with 900ml of water?
Or if I wanted to make a littler I'd need 20g BZAT and 980g alcohol?

Thanks,
Ben

Photo Engineer · Jan 26, 2016

In 1 Liter use the same proportions.

If 2% is 2 g in 98 G of alcohol (or water) then 2% is 20 g of BTAZ in 980 g of solvent. Exactly right.

PE

bence8810 · Jan 26, 2016

Proportionally I understand but can I use alcohol only as a solvent and then dilute the already dissolved BZAT + Alcohol mix with water if I mix it 20% and then dilute to 2%?

Also - what do you think about the developer I use? I am not a chemist and have no idea if this BZAT will work with any developer...

Thanks,
Ben

michaelorr · Jan 26, 2016

Then when incorporating the solution into a developer to add 0.2g of BZAT, one should measure the weight of the solution, not the volume to add. So, add 10 grams of solution, not 10ml. Is this correct? I am thinking of mixing photo formulary 130 with this BZAT instead of the kbr that comes with the kit, for use on the fomalux 111 silver chloride paper.

Gerald C Koch · Jan 27, 2016

When dealing with age fogged paper start out with 2.5 ml/l of 1% BZT solution to the print developer. Keep adding 2.5 ml increments until the fog is under control or until 10 additions total are made. At this point the paper is pretty much unsalvageable for serious work. Other darkroom workers may have a different criterion as to when to pull the plug on the paper.

It is fairly common to use 1% BZT and 10% potassium bromide as these concentrations have about the same antifog potential. Using different concentrations just complicates things.

bence8810 · Jan 27, 2016

Gerald C Koch said:
When dealing with age fogged paper start out with 2.5 ml/l of 1% BZT solution to the print developer. Keep adding 2.5 ml increments until the fog is under control or until 10 additions total are made.

Hi,

This is very conservative in comparison to what the box says my BZAT came in. It suggests 30ml of the 2% solution for every liter of developer.
Your suggestion is to give less than 10% of that and repeat until the desired effect is achieved but not over 25ml of 1% solution per liter of developer.
Even if I take your max value it's less than half of what the instruction of the box says.

Can this be?

Thanks,
Ben

Xmas · Jan 27, 2016

Suggest arbitrary criteria if you need to add more add more...
But the colour of the image may be altered.
Adding bromide warmer BZT colder.
Either will slow down the emulsion speed you might want to keep records so you could duplicate?

bence8810 · Jan 28, 2016

Hello all,

Here I go with my first test.
500ml of the earlier mentioned developer and the same photo with the same exposure etc developed twice.

1st: developer as it was (120sec)
2nd: like before +15ml of 2% BZAT (180sec)

The 2nd try started developing a lot slower - that's why I left it in longer.
It's also a lot less dark but I am afraid this could be from the killed developer?

Please chime in for this newbie. Thanks!

Ben

Confusing layout sorry. Top one with BZAT / bottom on with clean developer.

Wayne · Jan 28, 2016

Looks right to me, but I'm no technical expert. The 2nd one is darker and developed quicker because the fog gave it more "exposure". That's my non-technical expert opinion. I think the first one looks good, much cleaner highlights.

Gerald C Koch · Jan 28, 2016

bence8810 said:
Hi,

This is very conservative in comparison to what the box says my BZAT came in. It suggests 30ml of the 2% solution for every liter of developer.
Your suggestion is to give less than 10% of that and repeat until the desired effect is achieved but not over 25ml of 1% solution per liter of developer.
Even if I take your max value it's less than half of what the instruction of the box says.

Can this be?

Thanks,
Ben

BZT produces changes in image color and contrast. So it matters how much change someone can tolerate. Papers respond differently so it prudent to be conservative until you are aware just how much to use. BZT is not a cure-all and cannot really help seriously fogged paper.

bence8810 · Jan 29, 2016

Hello,

I think it's just a lack of experience on my end - I started printing exactly one year ago and don't yet know how to properly judge a print as it's out of the fixer.

To me the top paper in my above example is underexposed as there are no blacks. The patter on my son's robe was black. Without the BZAT the print developed darker and faster. I see the picture starting to show normally after 20 seconds but in the BZAT solution it took nearly a minute - hence I went on with the developing longer.

Will BZAT also slow development down or just contain the fog?
I do understand that not all paper can be saved it's just that I have such a large stash that I really want to try my best to salvage what I can.

Thanks,
Ben

How to mix Benzotriazole

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