Fomapan/Arista.edu Ultra 100-120: Pattern of small scratches, looking for culprit!
I've just started using Fomapan 100, in 120 size. My first film shows exactly the old-fashioned, creamy look I was out for, and a bit more: a pattern of small (approx. 0.2 mm in length) hairthin scratches, more or less homogeneously spread over the negative.
They are on all frames and most notable in the highlights though also present in less dense areas (just more difficult to see). One of the frames and a crop is in the attachment. Looking at the negative directly with the naked eye, the scratches seem to be not on either of the negative surfaces, but rather 'inside' the emulsion itself. It is of course impossible to tell by eye exactly where they are- the above is just what I think I'm seeing.
So what's going on? I used the same workflow as always and have never had these types of marks before. I took special care not to touch the image area of the film during the whole development/drying/storage/scanning-process, because I know from other 'small-brand' films (Adox/Efke in particular) how vulnerable the (wet) emulsions are. I definitely also did not squeegee the film, instead just let it dry by itself after a last bath in demi-water with some wetting agent added. Agitation during development/stop/fixing was by inverting the tank, no rotational movements. Washing ditto.
Anybody have an idea what's going wrong? I could (and will) shoot & process more Fomapan 100 (I have 29 left!) to see if the problem repeats itself, but suggestions are very welcome in the meanwhile. The only things that I can think of as a culprit are too rough agitation during washing (I fill the tank with water and invert, then repeat that several times at intervals) or too large temperature variation from the fixing stage to the washing (20 degr. C for developing/fixing and 25 degr. C for washing). Neither seem likely causes to me.
FYI: camera is a Hasselblad 500cm, development tank is a Paterson (latest type) for 2x135/1x120.