What did I do wrong? HP5+Pyrocat HD

[MMfoto]

I developed three batches of hp5 yesterday in Pyrocat HD. I'm sure I screwed something up when mixing the developer. Two batches came out fine. However, when I poured out the developer, from one batch, it looked like black pen ink. To my great delight (insert sarcasm), that batch did not develop at all. The negatives were clear and did not have frame numbers. Pyrocat HD is a two part developer. Obviously, my first assumption is that somehow I mixed up the two parts and added two parts of A or B instead of one part of both A and B. What I don't understand is why would the developer look so dark black?

 

[Simonh82]

I'm not familiar with the chemistry of Pyrocat HD but a lot of two part developers contain the developer in one part and an alkali to activate it in the other.

The black colour would be the anti-halation dyes from the film, these are broken down by some developers which is why you get clear developer normally. My guess is that you forgot the alkali part of the developer (if that is how it works) and this means the dyes weren't broken down in the normal way.

 

[Axle]

One thing that can affect Pyro developers is the introduction of acid into the mix. An acid stop or something.

 

[Ian Grant]

Sounds like the developer had oxidised in the third case. It only has a short life once made up and once it begins to oxidise and gets darker greeny/bule it's going to either cause over all staining or if left too long collapse.

It's the only developer I use these days (last 6-7 years) and I find it very consistent and reliable. However it does need to be made up with fresh Potassiun Metabisulphite as it's the dissolved SO2 that prevent oxidation of the Pyrocatechin.

Ian

 

[MMfoto]

To Simonh82: Yep, that makes sense about the dyes not breaking down, thus the developer looking so black. I must have doubled the part "A" with the developer, and left out the alkali. Thanks.

 

[c6h6o3]

To Simonh82: Yep, that makes sense about the dyes not breaking down, thus the developer looking so black. I must have doubled the part "A" with the developer, and left out the alkali. Thanks.

Even with no accelerator you should've gotten some image. For a while Sandy King, Pyrocat's inventor, was developing his negatives in two stages. Solution A only, then Solution B only. He always got an image.

 

[Rick A]

How long after mixing did you use the developer? Possibly contaminated developer by using dirty gear or switching caps on the bottles.