storing pyrocat HD developer

[jordanstarr]

Hey...

I've been using some 250mL clear jars for storing Pyrocat HD developer solution A and B and I've had good results with this. I mixed some about 3 months ago and the last of it is still going strong and hasn't oxidized. I'll be using much more of this developer in the future and would like to store it in 1L jugs. I have a bunch of empty 1L photo jugs that are empty and are begging to be used. I estimate that I will have this developer all used in 6 months.

Would it be spoiled by this time?

If not, what would I expect in terms of it getting weaker over time?

Thanks in advance.

 

[jgjbowen]

if you mix Pyrocat HD solution A in Glycol it will last almost forever. Mixed with H2O, not as long...more like 6-12 months.

Solution B will last forever mixed with H2O.

 

[jordanstarr]

Thanks for the answer...I actually went to go mix and I found out that I have a big jar of Sodium Carbonate instead of what the formula asks, Potassium Carbonate. When I ordered it, it was the same code, but a different chemical name. Anyone know if they can be substituted?

 

[sanking]

Yes, you can substitute sodium carbonate for potassium carbonate with ittle or no change in results.

To do so, mix a 20% Stock B solution of sodium carbonate, and use at 5X the amount of potassium carbonate to make the working solution. For example, where the formula with potassium carbonate calls for a working dilution of 1 Part A + 1 Part B + 100 Parts water, when using the 20% sodium carbonate B solution use 1 part A + 5 Parts B + 100 parts water.

Sandy King

Thanks for the answer...I actually went to go mix and I found out that I have a big jar of Sodium Carbonate instead of what the formula asks, Potassium Carbonate. When I ordered it, it was the same code, but a different chemical name. Anyone know if they can be substituted?

 

[jordanstarr]

Thanks for the answer Sandy.

....and would I still be using 750g of Potassium Carbonate per 1L of water?

 

[Philippe-Georges]

In the beginning, when I started to use Pyro-HD, I stored the A part, mixed in water, in a plastic bottle. It was a bottle that came from the Kodak E-6 kit and was well rinsed with hot water. After a while, the opal white bottle turned out dark grey, although it was kept in the dark. As I did not trusted it, I trashed the whole bottle (and the chemical) but did not test it (= stupid). Does this means that the A part has to be stored in glass instead of plastic (what I do ever since), or was this just some kind of an incident de parcours?

Philippe

 

[Ian Grant]

One point about storage of Pyrocat HD (no Glycol) is the type of container. In old Ilford 1 litre developer bottle I've found it last up to 18 months in a full/part used bottle, while the Metabisulphite is releasing SO2 there's no deterioration.

The choice of container is extremely important, I made a mistake storing early batches in small polythene 200ml bottle, there was some migration of Oxygen through the walls over about 3 months causing the developer to oxidise, and the plastic of the bottle to stain. Like Philippe I've seen similar happen with Pyrocatechin (Catechol) which migrated into the wall of the suppliers plastic storage container (Hopkin & Williams) and despite being sealed the Pyrocatechin was useless.

There is an APUG member in the plastics industry and in a previous thread he describe the different types of plastic bottles, some are ideal for developer storage.

Ian

 

[jordanstarr]

...the jar I used to use was a 250mL plastic on with an opening of about 2.5 inches in diameter, so there's lots of oxygen getting in and out I would imagine, but it worked for about 4 months. I think it has discoloured a little, but is still okay for now.

Thanks for your replies.

 

[waterlily]

I use light green 500 ml glass vinegar dispensing bottles. They have the same stopper size as wine bottles so I use the rubber wine stoppers designed to use with the air evacuation plunger. I used to use wine bottles but these green bottles are more transparent and I can see if the chemicals change color. I just evacuate the air as you would with wine after each developing session. I am not using Glycol and the chemicals last over 6 months.