Pyrocat HDC

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Barry Wilkinson

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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 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
 
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.
 
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
 
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.
 
Barry Wilkinson said:
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
Click to expand...

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
 
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.
 
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
 
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.
 
That's good to hear Barry. I might give HDC a try once my stocks of HD have finished.

Mike
 
Barry Wilkinson said:
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
Click to expand...

Having been 'making my own Pyrocat HD from 'scratch' for quite a long time (and being unaware of any 'update' to the formula and still have a stock of the required ingredients....I guess I'll have to use up what I have 'in stock before making any changes. might someone be able to forward a link for info on the 'reason and possible benefit' to we "fans" or the 'original' formulation.

Ken
 
Barry Wilkinson said:
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
Click to expand...
Hello Barry,
What is the formula for the HDC version?
 
I've been using Pyrocat HD for nearly 20 years. I've only mixed it in Glycol once, when I was travelling back to Turkey, and made up Part A double strength,to cut weight. That was around 15 years ago and I still have one 500ml bottle left, it's still OK no signs of Oxidation.

My experience is that Pyrocat HD Part A keeps well made up in water.

Ian
 
Ian Grant said:
I've been using Pyrocat HD for nearly 20 years. I've only mixed it in Glycol once, when I was travelling back to Turkey, and made up Part A double strength,to cut weight. That was around 15 years ago and I still have one 500ml bottle left, it's still OK no signs of Oxidation.

My experience is that Pyrocat HD Part A keeps well made up in water.

Ian
Click to expand...
Ian,

I was not suggesting it did have a short life but I prefer not to use water if necessary. I have found that HDC is easy to mix and I have never had a failure.

Barry
 
Keith tapscott. said:
Thanks Barry,

I see that it's about half way down the page, but I must have overlooked it the first time.
From what people are saying on the forum's, it's Sandy King's favourite of the variants.
Click to expand...
Hi Keith,

Glad you found it. Sandy has been using it for years.

Barry
 
Barry Wilkinson said:
Hi Keith,

Glad you found it. Sandy has been using it for years.

Barry
Click to expand...
One thing that does puzzle me is that it says to start with 750ml of Propylene glycol to dissolve the components, but doesn't mention anything about topping up with more glycol to make 1 litre.
Has that been omitted or is it just to make 750ml?
 
Sounds like it's been omitted......the formula is to make 1000ml, so you'll need to top up with glycol.

Mike
 
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