Pyrocat HD working solution colour change

Hi

I recently started using Pyrocat HD and I have only shot 3 films in it. The 1st and the 3rd were 400TX and I noticed that the spent developer had different colour in these cases. In the 1st case the used developer came pinkish out of the tank, whereas in the 3rd had a dirty, mostly tan colour. The developer is 3 weeks old and hasn't changed its colour, at least not perceptibly (looks like very weak tea). The negatives look fine and there's a lot of detail there, but I'm wondering if it is a sign of rapid deterioration of the developer. FWIW, it was mixed using deionised water and the Catechol used had a very light tan colour.

It is supposed to change color when spent. In the case of TX, the pink is the sensitizer Kodak uses, similar to Tmax. The dark tan is oxidation.

Yes, I assumed that the pink coloration was from the dyes in the film, but I'd guess the spent developer would look the same when using the same film.

The oxidation occurs when you agitate, introducing more O2 into the solution, causing it to turn darker. You want to see this result using pyro developers.

The color of spent developer really does not indicate anything useful. The color can be effected by various dyes in the film emulsion. Just ignore any color.

That was reassuring, thanks you all.

The longer you develop and the more you agitate, the more oxidation and discoloration of the developer will occur. Same time, same film, same agitation should yield similar results. That said, if one roll were significantly more dense than another, then that would likely affect color as well.

Best,

Doremus

Truth be told Doremus, the last film was developed for 12'', while the first for 10''. Probably denser too, so it might make sense. Thanks a lot.