Pre soak problem

Yesterday I tray developed a batch of 7x17 HP5 in Pyrocat HD. The negs were quite thin with a pink tinge. I associate pink tinges with under-fixing, but this was a 5 minute fix and it was fresh. The negs look like I may have underexposed. The strange thing is this -- the pre-soak water was completely clear. This happened once before with Tri x 8x10 negs, but only once. The only variable I can think of was that I used distilled water for the pre-soak and filtered for the rest of the process. But even that doesn't make sense. Any ideas?
Patricia

That does sound strange. When you say the fix was fresh, do you mean a new batch or had you maybe run a small amount of film through it? The pink can also come from TMax films so if you had run any of that through your fix, that could be the cause of it. Did you check to make sure you did the proper dilution? I've never had distilled water cause a problem before, so personally I don't think that could be it.

Wish I was more help.

The fix was freshly mixed, meaning it had no previous use, and I was accurate in my measurements.

If I good understand the problem is only the color of film (pink tinges) – you don’t like. For this is good to put on a little film in a very caustically solution (sodium or potassium hydroxide 40 – 50 g/1000 ml water. Normal water is ok.). In 10 minutes at 45 – 50 ˚C emulsion goes from film. You make a good wash and after dryer see the color of the base.
In the last time I work with out data films. Many of them are color slide films. After three years of data films came the problems, in the first place the fog. Many time I wash old film before the process is good (sometime I work with alkaline solution – sodium carbonate). Never have I tried washing the b/w films before the process but I thing is not bad. I don’t work with modern b&w films, only very few.
For me, distilled water for the pre-soak – is not a different with normal water. The presence of an alkaline component (like sodium or potassium carbonate 10 – 15 g/1000 ml water) can change many things. After alkaline solution I make a good wash. The time for developer can be short that normal because the layer of emulsion is gonfler and the reaction with developer are faster.
For each film, I think, you have a good ph (alkalinity) for the pre-soak.
The fresh fixer is important.

George