blotchy first attempt at C41 - any ideas?

[Jan Normandale]

I'm about to start using a CPE 2 and have been using a Paterson tank. Are there any threads showing images using a Jobo vs "by hand" developing. The times are considerably different and I'm wondering how to deal with the "temp loss" curve of manual vs continual temp of Jobo with substantially shorter developing times.

[OzJohn]

Like PE I've tried C41 processing at lower temps and could never make it work. When I was developing colour I always used Kodak Flexicolor chemicals but I doubt that there is any magic ingredient in Tetenal any other brand that would improve the result. To prove the point to my own satisfaction I once shot four identical films under studio conditions using colour targets as the subject and had one processed by a pro lab, another at the local Kodak 1 hour lab and I developed the other 2 - one at 37degC and the other at 24degC, both in Flexicolor. Can't remember the timing I was using for the 24deg process but I recall it was long and based on a consensus of advice gleaned from various sources at the time (mainly magazines) and seemed to produce correct overall density with negs that looked OK.
I learnt a lot about neg development from the experiment because not only did I establish that the negs developed at 24deg contained a virtually uncorrectable cyan cast but also that the standard of my processing even at 37deg fell a bit short of both the lab processed films - printable but lacking their neutrality and clean colours. There was very little difference between the dip and dunk pro lab result and the 1 hour lab down the street.
The experiment caused me to get a Jobo machine for film processing. After much trial and error I was able to get results pretty much identical to a lab but I always re-ran the comparison test at least half yearly until I stopped processing colour film a few years ago.

OzJohn

[hpulley]

With plastic Paterson Super System 4 tanks and a simple water bath I get excellent temperature control. In fact I tried without a bath once using a higher starting temperature and it works too but I feel better using the water bath so that is what I stick with. 39C/102F at the start works well for me, I just have to look at the stopwatch to make sure I don't do an unintentional push as 3:30 goes by fast...

[Greg Davis]

There is a thread about the Rollei C-41 kit here somewhere. The kit claims you can process at 20ēC with extended times, and I tried it with comparisons against Kodak Flexicolor at both 20ēC and 38ēC. All results at 20ēC were awful. With scanning and heavy color manipulation in Photoshop I was able to almost match the color from the normal Kodak stuff at 38ēC, but saturation was off and it just wasn't right.

I have used a warm water bath to do standard inversion processing with great results, but I too use a Jobo for my color work.

[Chris Douglas]

I use Unicolor kits but I suspect they are similar. I use a metal 16 oz tank with an empty spiral on top, and use 15 oz of chemistry. Two inversions every 30 seconds, with thermostatically controlled water bath. I generally follow the directions and always get good results. Good luck.