Ilford PQ has gone Brown

[bvy]

My 1 liter bottle of Ilford PQ is brown like coffee. I purchased it in the summer, and at present it's maybe half full or a little less. The thing is, I sprayed a bit Bloxygen (argon) in the bottle each time before sealing it. So I was surprised that this has happened. Is this oxidation?

I made a working solution (1+9) and it still produces strong blacks, though it's a little hard to see what's developing through the muck. I'm deciding if I should use it for a few noncritical pieces until I can get a fresh bottle...

Thanks.

 

[Simon R Galley]

Dear Bvy

It certainly sounds like it has oxidized, I wouldn't use it if I were you if you are developing FB .. in saying that if it is still working and you are using RC and use a stop it should not affect the longevity of the print.

Please refer to our tech sheets on best practice of 'keeping' part used chemicals. I noticed you had replaced the air with Argon, it s best to decant to ensure no air at all.

Simon ILFORD Photo / HARMAN technology Limited

 

[Gerald C Koch]

It is far better to decant developer into several smaller bottles than attempt to displace the oxygen in a large half-full bottle. In addition try to purchase a developer size that can easily be used within the shelf life of the product. If this is not possible then a product with a long like HC-110 or Rodinal is a better choice.

 

[NB23]

Sure, use it.
It's developing fine? So what's the problem? Develope for the whole recomended 2 minutes, stop abd fix.

 

[bvy]

Thanks. I'm using RC paper and will decant the next batch to smaller bottles filled to capacity. Usually 1+9 fully develops in one minute; with the brown stuff, I'm having to go two minutes or more. Time to restock.

 

[ChuckP]

I've just got a new bottle of PQ and want to spit it up into smaller bottles. I've got some bottles but they are a little too large to split the PQ evenly and fill to the top. Is it better to leave some air in the bottle or add some water to completely fill the bottle? I lean to filling with water and taking this in to account when figuring dilution. Also is there a limit to how much water to PQ solution that can be used in a full bottle for long life? What I mean is does a say 1:1 full bottle last a shorter time compared to a factory stock solution full bottle?

 

[Gerald C Koch]

Don't add any water to the concentrate. Fill each bottle to the top and then use the partially filled bottle first. The bottles should be made of glass or PET plastic. Other plastics can be permeable to oxygen.

 

[naaldvoerder]

PQ Universal goes off quite rapidly, I have found. It is lovely, however, in combination with my stock of Forte Polywarmtone.

 

[ChuckP]

Thanks Gerald. That makes more sense. Not sure what I was thinking about with the PQ as your method is what I have been using for Dectol for years.

 

[bvy]

Just for the record, I had the 500ml bottle, not the liter (if there is such a thing). I agree it discolors (oxidizes) quickly, but this is the fastest I've had a bottle go. Nice stuff though. It's funny, because when I was naively buying my first darkroom supplies, I think I mistakenly bought this instead of the multigrade developer. Now it's what I know and continue to use...

 

[Mark Fisher]

If the bottle is polyethylene (more than likely), it lets in oxygen fairly readily so filling it with Blox, argon or whatever doesn't really help that much. Glass is best. PET soda bottles are the best of the plastic bottles.