Has MY PyrocatHD (A) Died ?

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Ian-Barber

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This is what my Part (A) Stock PyrocatHD looks like. I purchased these in July 2017 and they were mixed in Glycol

Small Left
This is the A solution I am using now which is stored in a 200ml glass bottle albeit the bottle is only 1/2 full. It appears to have a very slight syrup feel to it as I poured it in to the graduate.

Large Right
This is from a full 500ml plastic bottle which was full to the top and taped round the screw top. This is a bit like syrup as I poured it into the graduate.

Any PyrocatHD users know if either of these look bad ?

IMG_0042.JPG
 
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First, if mixed in glycol, part A will be somewhat "thick." I mix my own Pyrocat-HD, but I can tell you that mine is clear. I would say that the small graduate on the left is going bad from oxidation, but should still be usable. The large graduate on the left looks bad to me. I've never had any version of Pyrocat turn that color. I'm a little surprised that the solution in glass has oxidized even to that extent in one year! Odd...
 
Alan9940 said:
First, if mixed in glycol, part A will be somewhat "thick." I mix my own Pyrocat-HD, but I can tell you that mine is clear. I would say that the small graduate on the left is going bad from oxidation, but should still be usable. The large graduate on the left looks bad to me. I've never had any version of Pyrocat turn that color. I'm a little surprised that the solution in glass has oxidized even to that extent in one year! Odd...
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The one on the Right has never been opened but it has been stored in a plastic HDPE bottle. It certainly is a different color and is thicker when pouring.

The one on the left (small) is in a glass bottle but the bottle is only 1/2 full. I am wondering if air has been introduced when I syringe it out.
 
Sorry, Ian, I meant to say "right" above. I doubt that syringing it out is a problem, unless you contaminated it somehow. I mix small quantities at a time and store in brown glass bottles. I, also, use Tetenal Protectan as I use the contents. That's probably unnecessary, but it makes me feel better. ;)

I just had a thought... Do you keep your A and B solutions separate? Use one syringe for A and another for B? Are they marked A or B avoiding any cross-contamination issue? Now that I think about it that large graduate on the right looks as if it has been partially mixed; though, again, I've never seen any Pryocat solution that color.
 
Both have gone off, the small one has just started to oxidise it might just be usable as Alan says, the other has collapsed.

I've been using Pyrocat HD for 14 years now, the only time I've had Part A go off was my own fault when I used small bottle that allowed oxidation through the low density plastic walls. I mix Part A in de-ionised water, it keeps up to 4 years, this is not a one off bur regularly, I have developer stored both here and in Turkey. The secret is the Metabisulphite used in Part A muse be reasonably fresh and the correct bottles,, I'm talking stored in partially filled bottles.

Friends use Pyrocat from the Formulary in the US, they say that it has a shortish life, Peter Hogan sold Pyrocat HD here in the UK as Precyscol a friend in Turkey was using it and it would last about 3 months before starting to go off, in both cases it was poor quality bottles.

Ian
 
Ian Grant said:
Both have gone off, the small one has just started to oxidise it might just be usable as Alan says, the other has collapsed.
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Ian, would it be fair to say that the one on the right which has never been opened since I bought it in July 2017 has died because it has been left stored in the plastic bottle it was delivered in?

So storin in Glass and not plastic bottles seem to be the key here but because we only use around 5ml per development, the contents of even the glass bottle is going to drop. How do you deal with any air in there, obviously we can't squeeze it out.
 
Alan9940 said:
Sorry, Ian, I meant to say "right" above. I doubt that syringing it out is a problem, unless you contaminated it somehow. I mix small quantities at a time and store in brown glass bottles. I, also, use Tetenal Protectan as I use the contents. That's probably unnecessary, but it makes me feel better. ;)

I just had a thought... Do you keep your A and B solutions separate? Use one syringe for A and another for B? Are they marked A or B avoiding any cross-contamination issue? Now that I think about it that large graduate on the right looks as if it has been partially mixed; though, again, I've never seen any Pryocat solution that color.
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Yes Alan, I have 2 separate syringes both labelled A and B and are stored in bags in separate boxes. In fact, the Pyrocat A+B solution are also in separate boxes and never really see each other.
 
Ian-Barber said:
Ian, would it be fair to say that the one on the right which has never been opened since I bought it in July 2017 has died because it has been left stored in the plastic bottle it was delivered in?

So storin in Glass and not plastic bottles seem to be the key here but because we only use around 5ml per development, the contents of even the glass bottle is going to drop. How do you deal with any air in there, obviously we can't squeeze it out.
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Ian, I store my Pyrocat HD in plastic bottles, usually re-using old Rodinal or 1 litre Ilford PQ developer bottles (some must be 30+ years old), and as I use the developer the contents drop, that's never been a problem.

Using Glycol isn't a guarantee of long term storage if the wrong plastic bottles are used by the supplier, also there's a question of how much Glycol. The problem is some of the components have to be dissolved in water as they won't dissolve in Glycol so we don't know how much water and how much Glycol.

I made up two Rodinal bottles of double strength Pyrocat HD in Glycol about 8 years ago to take to Turkey, only double strength to cut the weight when flying, I mixed one bottle to normal strength once there, I also bought the Carbonate there. We returned to the UK 7 years ago and it sat in Turkey unused, I brought it to the UK last year - I've just checked it and there's no oxidation same colour as when first mixed.

Because the Pyrocat HD (Pt A) I make up keeps so well (up to 3-4 years) I've never made it up with Glycol again. It's the Metabisulphite that prevents oxidation, once that breaks down to Sulphite there's no protection for the Pyrocatechin. Once mixed for use the Carbonate converts the Metabisulphite to Sulphite which is why it has a short life once mixed.

Ian
 
Ian Grant said:
Using Glycol isn't a guarantee of long term storage if the wrong plastic bottles are used by the supplier, also there's a question of how much Glycol. The problem is some of the components have to be dissolved in water as they won't dissolve in Glycol so we don't know how much water and how much Glycol.
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The only place in the UK I could find this ready mixed was from Wet Plate Supplies in Cambridgeshire. I have no idea how much water or Glycol he used. I am now at a station where I need to order some more but he only supplies it in with 500ml or 100ml bottles. 500ml works out cheaper but I guess only if you are a regular user.

I may have to get the 100ml bottles which in theory should get me 20 sheets developed if developing single sheets at 1+1+100.
 
Nothing against the Formulary, but the fact is that the only time I've had Pyrocat go bad it was from them. I gotta believe they know how to mix chemistry, so I'm thinking it's the bottles. If you don't mix it yourself or you're not a regular user of the product, I'd suggest buying it in smaller quantities; even though it cost a bit more.
 
Alan, friends in Canada/US tell me it's the bottles used by the PF that are the issue, not the developer itself

I've just mixed up 2 litres of fresh Pyrocat HD Part A in de-ionised water, initially the solution was cloudy and more like the colour of Ian's larger right hand side sample however now an hour later it's a very pale straw colour this change when mixing is quite normal normal, you get some slight oxidation of the Pyrocatechin but the Metabisulphite redues it back. Happens when mixing some other developers as well.

This is 4 year old Pyrocat HD Part A, no Glycol stored in a part full 1 litre bottle:

upload_2018-7-29_16-41-3.png

This is 8+ year old Pyrocat HD 2x normal strength in Glycol:

upload_2018-7-29_16-43-19.png

If diluted to normal strength they'd be the same colour.

Neither have begun to oxidise, there's very little left in the first bottle (top image) and I know I made up a large batch soon after moving into my current house in April 2014 and it's still as good as when I made it up.

Ian
 
Yeah, I always suspected it was the bottles. I mix small amounts, in glycol, and store in brown glass bottles (Boston Rounds.) Since I store a small quantity, it doesn't take me years to use it. I vaguely remember many years ago that I mixed up a batch using distilled water and the A went bad before I used it all. Could have been contamination on my part; I never bothered to try and track it down.

Overall, I find Pyrocat to be a very stable and economical developer to use. Plus, it works competently in the various development workflows I use--rotary, normal (1:1:100), stronger (2:2:100 for pt/pd), semi-stand, and EMA.
 
If we were doubtful about the quality of a plastic bottle, would it help to reduce or prevent oxidation if it were stored under water inside another container? I don't suggest that this is ideal, but it might be a stop-gap. We might boil the water first, to remove dissolved gases.
 
There's dissolved gases like Oxygen in water even distilled unless it's literally coming straight from the still, after that it rapidly absorbs gases from even minimal contact with air.

I've not found choosing good plastic bottles an issue once I 'd had a problem with small low grade bottles, every batch has kept well since then, and did before as well.

Ian
 
Fair enough. The idea crossed my mind and I wasn't sure.
How do we identify the correct plastic bottles if we're not using glass? The bottles that I buy developer in look remarkably ordinary.
 
As a matter of interest: My last two mixes of Pyrocat HD in Glycol have had the same 'red' colour as Ian Barbers after mixing but are still working perfectly after several months. The Pyrocatchetol was from Wet Plate Supplies. My earlier mixes used Pyrocatchetol from Silverprint and were a straw colour. All other chemicals from the same batch and were mixed in Distilled Water.
 
Yes Ian I also mixed the Silverprint chemicals in Glycol. I do not know why the WPS Pyrocatchetol turns out red but it works for me.
 
I should also say that I was concerned when I first saw the colour but on checking with a friend his was the same colour.
 
Barry Wilkinson said:
Yes Ian I also mixed the Silverprint chemicals in Glycol. I do not know why the WPS Pyrocatchetol turns out red but it works for me.
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I think Ian G is the person that really understands the ins and outs of this developer.
In July 2017, @Keith Haithwaite and I bought some from Wet Plate Supplies and he has also reported that his has this reddish colour but also states that some he bought from another supplier is more of the straw colour.

Whilst I was at Ian G's home today, I bought some from him which he had just mixed and that has the straw colour albeit it was not mixed in Glycol. Unfortunately, I have now thrown 500ml of the reddish colour away so I can't say how it would have performed.

Its strange how the WPS mixture we all have is producing the reddish colour though.
 
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