arothaus
Hi,
Yesterday I dug out two rolls of 120 CHM 400 from the box, and one of the two films has small holes in the emulsion. The spots are about 1–2 mm in size, with around 5–6 scattered across the film. I had the same problem once with a Foma 400; at the time, I thought it was down to a faulty emulsion (there was a bit of a thing with Foma back then). Otherwise, I’ve never had any problems with film.
Development parameters: Rodinal 1+50, 19 degrees, 10 minutes, CHM 400 at 200 ASA. Intermediate rinse, two-bath fixing with Amaloco X55, ‘Ilford’ final wash, Calbe wetting agent in deionised water.
Could this be down to the development, or are problems with the emulsion a possibility?
Regards,
Andreas
MirkoBoeddecker
Andreas,
Are the holes on just one roll of film or on several, and if so, are they on just one photo or spread across the whole roll?
Are the holes circular or not?
Thanks for your reply.
Best regards,
Mirko
arothaus
Hi Mirko,
The Läher are only on one film – there are several images of them there. They are actually a bit smaller than I first thought; the largest hole is about 0.5 mm in diameter. The wheels aren’t perfectly round, but rather a bit worn and angular.
Best regards,
Andreas
MirkoBoeddecker
Hello Andreas,
Of course, I can’t judge this accurately from a distance, but casting defects are usually round or oval in shape and warped in the direction of casting, as they are caused by air bubbles that have formed in the emulsion and end up on the film (even though manufacturers naturally try to prevent this).
Normally, these areas are detected during quality control and cut out.
However, if it’s only on a few frames of a single roll, it’s possible that the spot slipped through – this can’t be ruled out – regardless of the manufacturer (in this case, Ilford).
However, sharp, eroded rings are more indicative of mechanical damage to the wet emulsion.
Or of a stop bath that is too strong combined with an alkaline developer. In that case, the emulsion can literally be ‘blown off’ the film if gas forms in the stop bath.
Best regards,
Mirko
