DIY C-41 with Jobo CPE (temperature deviations)

[cdacowan]

So I bought a Jobo CPE with lift to do home processing, and I thought C-41 would be easiest as I have lots of C-41 film.

I bought a Fuji Hunt 5 litre kit and I tried on 2 rolls of 35mm Portra (at the same time), and one roll came out ok, I am yet to scan it, but visibly it was ok, and the other has these blue frames every 5th frame or so (this might be from getting my fingers all over the film as I was getting used to the loading process for the 1500 reels.

So my problem is this, is the analogue temperature scale which I set to 38.5 deg as there would be a temperature loss when pouring the chemicals in and out, form the ideal 37.6 ±0.15 according to the fuji manual.

Should I switch to doing E6 as it is less precise.

 

[tnabbott]

Get a thermometer. I have the CPE and get very satisfactory results from both C41 and E6. But I always relied on a separate thermometer, which I stick into the water through the odd small aperture to the right of the tank aperture.

Incidentally, E6 is really no less precise than C41. Temperature for both is critical.

 

[hrst]

Hey if you have another roll OK and another not and are having some kind of stripes, it is not any temperature problem.

You probably had error in loading the reel and had the film in contact with itself so that chemicals did not reach the emulsion everywhere. This is one possibility.

In my experience, touching the film when feeding on the reels does not cause any problems. In extreme cases, it might cause some damage but they would look more like fingerprints and scratches.

 

[Photo Engineer]

But you can prewet with 100F water to bring the drum, reel and film up to temperature, and then run the process. This is much more stable.

PE