PQ Universal and benzotriazole question

What About Bob · Jun 6, 2025

I have the ingredients to make up PQ Unviversal. I am seeing the recipe as ID-62 and there are two versions of this recipe. One regular mix and the other being 2.5 times the strength. Which recipe would be used toward the Ilford black and white reversal process for the first and second developers when mixing to the 1+5 and 1+9 working dilutions?

One last question: I noticed that benzotriazole is a listed ingredient. It's an antifog agent. I read it is also used to shift the warm tone on papers so I was wondering if this agent was needed when developing film? Thanks

koraks · Jun 6, 2025

Are you referring to this page? http://www.lostlabours.co.uk/photography/formulae/developers/devID62.htm (@Ian Grant's excellent work)

What About Bob said:
One regular mix and the other being 2.5 times the strength. Which recipe would be used toward the Ilford black and white reversal process for the first and second developers when mixing to the 1+5 and 1+9 working dilutions?

It's the same developer; the more concentrated version is intended for dilution to effectively the same working strength as the other formula. The concentrate takes up less space in storage. It's the same thing, just less water.

What About Bob said:
One last question: I noticed that benzotriazole is a listed ingredient. It's an antifog agent. I read it is also used to shift the warm tone on papers so I was wondering if this agent was needed when developing film? Thanks

For fresh film and certainly if you're going to add a strong silver solvent to your first developer (thiosulfate, thiocyanate), the benzotriazole I would consider as pretty much superfluous.

What About Bob · Jun 6, 2025

koraks said:
Are you referring to this page? http://www.lostlabours.co.uk/photography/formulae/developers/devID62.htm (@Ian Grant's excellent work)

It's the same developer; the more concentrated version is intended for dilution to effectively the same working strength as the other formula. The concentrate takes up less space in storage. It's the same thing, just less water.

For fresh film and certainly if you're going to add a strong silver solvent to your first developer (thiosulfate, thiocyanate), the benzotriazole I would consider as pretty much superfluous.

Thanks koraks

That is the page. Excellent work and valuable information.

I'm itching to try this out. Just waiting for a few extra purchases to come in. One of them being a calibration weight for the new scale that I recently bought. Measures out to two decimal places. All of my other scales came with calibration weights except for this new one. The shipping cost was more than the weight, lol.

What About Bob · Jun 6, 2025

The permanganate that I bought is reagent grade but the bisulfate is not. It was bought at a pro chemical and dye shop. I was reading the technical sheet on their bisulfate and it is listed as technical grade >90%. The sheet doesn't list the other <10% Should I be concerned about this? The bisulfate at Amazon looked like it had additions to it so I resisted buying from there.

The only other place I could find this stuff was at the Forumulary but the last time I was there, some years ago, the shipping costs were phenominal.

John Wiegerink · Jun 6, 2025

What About Bob said:
The permanganate that I bought is reagent grade but the bisulfate is not. It was bought at a pro chemical and dye shop. I was reading the technical sheet on their bisulfate and it is listed as technical grade >90%. The sheet doesn't list the other <10% Should I be concerned about this? The bisulfate at Amazon looked like it had additions to it so I resisted buying from there.

The only other place I could find this stuff was at the Forumulary but the last time I was there, some years ago, the shipping costs were phenominal.

Don't get your bisulfite mixed up with bisulfate or you'll be in big trouble.

Raghu Kuvempunagar · Jun 6, 2025

If your Bisulphate and/or water used to miix the bleach has chloride as impurity, the bleach acts as partially rehalogenating. As a consequence, not all metallic silver is removed by the bleach with some getting converted back to Silver Chloride. Unless removed through an additional step involving dilute Ammonia, this residual Silver Chloride can cause imperfections in the final positive.

What About Bob · Jun 6, 2025

I will be using distilled water. The data sheet doesn't list what the other percentage is. This is the stuff I bought: https://prochemicalanddye.com/product/sodium-bisulfate

What About Bob · Jun 6, 2025

Long time ago I developed color slides. This will be my first time with black and white reversal. I will definitely keep records of this whole process. I can't wait to get crackin with this.

More than likely I will be navigating back to using the SS tank and reel for this because of the lower chemistry volume and also dealing with the reloading of wet film after re-exposure. Last year when I was developing the old C-41 film with the plastic AP tank, after the first process run, I gave a little bit of time and even briefly used a hairdryer on low to dry the reel and even then I could not get the second film for processing on to the reel. Those reels have to be bone-dry or else you ain't going nowhere. Good thing I had a secondary plastic reel to switch back and forth between processing films.

lamerko · Jun 7, 2025

Is there any specific reason not to use the D94 as per Kodak's specification?

Ivo Stunga · Jun 7, 2025

What About Bob said:
dealing with the reloading of wet film after re-exposure. Last year when I was developing the old C-41 film with the plastic AP tank, after the first process run, I gave a little bit of time and even briefly used a hairdryer on low to dry the reel and even then I could not get the second film for processing on to the reel. Those reels have to be bone-dry or else you ain't going nowhere.

After reexposure to light I wet my Paterson reel and have little problems ratcheting film onto the reel. If there are problems starting /gripping film - emulsion side up usually helps.
Film can get harder to spool or might even stop doing so at the end of it. Again - water helps to lubricate things... So I submerge my film with the reel, and end the process under water.

Raghu Kuvempunagar · Jun 7, 2025

lamerko said:
Is there any specific reason not to use the D94 as per Kodak's specification?

Wouldn't your first development time be very short (two minutes or less) when you use D-94?

PQ Universal and benzotriazole question

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