Pyrocat HD precipitation problems

T

tykos

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Hi, first post in this forum.
A couple of months ago I mixed Pyrocat HD for the first time. I needed a small quantity of it (100ml), so I had to measure very little quantities of phenidone and potassium bromide.
I solved this problem by creating a 1% phenidone solution in propylene glycol and a 1% KBr solution in water (I was not able to dissolve it in glycol, is it a thing?).
I then prepared my Pyrocat HD dissolving these and all the other components in warm propylene glycol.

Now, two months later, my Pyrocat HD has a lot of deposit and precipitation:
IMG_3048.jpeg

For what is worth, even my 1% phenidone solution has the same problem.

What could have caused this?
How can I solve it? I tried keeping the bottles in hot water and stirring the solutions, but no progress were made.

thanks
Michele
 
Consider switching to water-based preparation of Part A. If you use fresh metabisulphite while making Part A and store the concentrate in tightly capped glass bottle, the water-based concentrate should remain fine for a long time. I've some from four years ago and it is still good.
 
I used glycol because I read about it keeping for a long time and I mainly use other developers.
Do I have to throw it away now?
 
Probably not enough water to keep the Mertabisulphite in solution. You could measure what you have and add the same amount of de-ionised water. Then use twice a much Part A when using it.

Pyrocat HD PArt A keeps 3 to 4 years made up in water.

Ian
 
But I’ve got the same problem with the phenidone concentrated solution, and there’s no bisulfite in it
 
What concentration ? Typically it should be 50g per litre.

Ian
 
tykos said:
I used glycol because I read about it keeping for a long time and I mainly use other developers.
Do I have to throw it away now?
Click to expand...

No need to throw it away. There are two solutions. The first solution is do what Ian suggested. Measure the volume of Part A that you have in the bottle and add the same amount of distilled/RO water to it. The precipitate should dissolve completely after water addition. Use twice the volume of the new Part A for the working solution. Test on non-critical film before using the new Part A on critical work.

The second solution is to heat water to ~80 C and place the bottle in the water bath till the precipitate redissolves in glycol.
 
(many months later)
i diluted my part A (which was mixed in glycol) with an equivalent part of distilled water and brought it all to 70-80°C. The sediments were almost all dissolved.
After a few days, no sediment like before but the mix is quite cloudy.

I didn't try this with my phenidone solution because i'm afraid it would go bad with water.

What could have caused all these problems? Bad/impure chemicals? Bad glycol? some procedural errors on my part?
 
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