problem in developing sheet film
Since some time, I am plagued by a very annoying problem when developing 8x10" sheet film for which I would really appreciate some advice. The problem is visible in the attachment, a scan of a negative which I brought back from my recent journey, and which is spoiled by it: look at the circular patches on the negative with a peculiar pattern inside, formed by respective areas of lesser density.
The negative was developed in Sandy King's formula of Pyrocat HD (which I have used for years) in a separate dish into which it was transferred after 5 minutes pre-bath. 1st Minute continuous agitation, then once every 3 minutes, dev.-time: 16 minutes. I have developed 6 negatives in six dishes into which they were transferred, 2 at a time, from the pre-bath. When transferring I wore surgical dispensary gloves, and, this is how I can imagine the patches to be caused, I sometimes gently pressed the film into the developer, emulsion side up, with my gloved finger tips, to make sure it gets immersed.
I have used this method for years, never encountered such problems until recently; on retrospect these patches seem to have started when I began using distilled water for the developer. They happen with both sorts of films I currently use (Ilford HP5 and Adox 100).
By the way, I also develop 4x5" negs in a tank, and there I have never seen this problem.
I would like to keep the distilled water, but obviously this problem would makes this prohibitive if it really causes the patches.
Does anybody have suggestions, or has encountered such a problem her/himself?