Pyrocat HDC

Barry Wilkinson

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Registered User
Has anyone tried Sandy King's Pyrocat HDC fomula? Sandy says that its the formula he now uses. The formula omits the Sodium Metabisulfite and Potassium Bromide, adding Ascorbic Acid.

Barry
 

mpirie

Member
Registered User
I haven't tried his new formula yet Barry, as i have a stock of PF kits and recently bought the chemicals to start making my own.

Do we know what advantages the Ascrobic Acid version has (apart from being environmentally safer)?

Mike
 

Barry Wilkinson

Member
Registered User
Sandy King suggests mixing the Metabisulfite and Potassium Bromide in HD formula with 50-75ml of hot water to help them dissolve before adding them to the base mix. This introduces a small amount of water into the Glycol which some would prefer not to be there for longevity. I am on the fence with this one but I like the idea of having to mix less ingredients. I also have a good stock of HD but I will give this a try as soon.
 

Ian Grant

Well-Known Member
Registered User
You need to use a small quantity of warm water to dissolve the Metabisulpite and Bromide if your going to make the Glycol version as neither chemical will dissolve in it.

I think the Pyrocat HD I mixed in Glycol with the samll amount of water is js just over10 years old now. It hasn't oxidised I ought to test it, however the 3 year + shelf life in water is more than enough.

Ian
 

Barry Wilkinson

Member
Registered User
Indeed Ian, I have some Pyrocat HD mixed in Glycol containing 50ml distilled water that I am currently using with success which was mixed in 2017. I am still however interested in HDC and will make some for testing soon.
 

KenS

Active Member
Registered User
Has anyone tried Sandy King's Pyrocat HDC fomula? Sandy says that its the formula he now uses. The formula omits the Sodium Metabisulfite and Potassium Bromide, adding Ascorbic Acid.

Barry
i have to admit that I was not aware of any 'modifications' to Sandy's Pyrocat HD (which I have stated both here (and elswhere) that it has been the only film developer 'in my darkroom' for many years. Might I inquire of those who are currently using Pyrocat HDC

"What are the benefits over the 'original'formulation?"


Ken
 

Barry Wilkinson

Member
Registered User
Although I have not had any issues with my Pyrocat HD in Glycol which includes around 50ml of distilled water I think it would be preferable to not include any water. The HDC formulae omits the Sodium Metabisulfite and Potassium Bromide thus removing the need for the water. Sandy King has recently said on another forum that this is the formulae he has been using for some years and cannot see any significant difference in results between HD and HDC. I have still to test it.
 

Barry Wilkinson

Member
Registered User
Words from Sandy king...

Some of the chemicals in the -HD formula, especially metabisulfite and bromide, need a lot of heat to go into solution in glycol, but they are not really necessary in the glycol formula anyway so even if not in solution in the stock solution the working solution should work fine.

However, I have been mixing and using only the -HDC formula for at least 6-8 years. -HDC substitutes ascorbic acid for the metabisulfite and bromide with same results, and all of the chemicals go into solution in glycol easily at 150º F.

Barry
 

Barry Wilkinson

Member
Registered User
As a brief follow up...

I have now used Pyrocat HDC and I have not seen any difference in my negatives when compared to Pyrocat HD. I will create some test negatives at some point to do a proper analysis.
 
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