digiconvert said:
I had read about the need for super accuracy of temp (+- .5deg C) and timing (I use a coltim accurate to within 30"), the need for a rotary or slot processor etc. etc. but I am getting reasonable prints and negs now (not always consistent filtration but it doesn't take much to get there). Why is it working ? Am I easily pleased ? Am I incredibly lucky ? or is colour work actually not quite the black magic some make it out to be ?
I find it easier than PS and scanning negs.
Some other questions
-Would a drum make life easier or harder ? (still room temp, hand rolled)
- Do I need to take care about the RA-4 chemicals ? (after 20 years in various labs I have skin like a rhino)Comments welcome
After a few years of processing C-41, RA-4 and E-6, accompanied by sundry mistakes in processing, I have come to the conclusion that: temperature control (both in terms of adhering to the desired temperature on the thermometer and uniformity solution-to-solution) is NOT that critical.
Originally, when Ektachrome "home processing" first became available, the processing temperature HAD to be controlled (no slack permitted, according to Kodak) to be controlled to 75 degrees F +/- 1/4 degree. There is, first *no way* one can tell if that is happening; even the top "Laboratory Grade" Kodak thermometers were only guaranteed to +/- 1/4F; and second there is *no way* the temperature
could be controlled that accurately.
The ideal processing temperature for C-41 is 38 degrees C. The ideal processing temperature for RA-4 is 35 degrees C. I use a JOBO CPP-2 (JOBO claims a temperature accuracy, using this puppy, of +/- 1/3 degree Celsius).
You've guessed it - the most common mistake I've made is to process C-41 film at 35C, and RA-4 at 38C.
The results? Simply put, I can't tell one whit of difference, either by eye OR using a color densitometer. Apparently there are other factors; chemistry uniformity, film and paper characteristic variations, lighting conditions and exposure, the phase of the moon, whether or not Mars is in Capricorn ... that have a far more significant effect than does processing temperature.
I think that the requirement of +/_ 1/4 degree F was a CYA ploy for Kodak. If anyone complained about their results, Kodak could always dodge the problem by saying... "You didn't control the processing temperature closely enough"... and they would (to a probability of 99.99999999%) be right... the processing temperature would NOT have been controlled that accurately .. but equally probably, that would not have been the cause of bad processing, either.
A drum WOULD make processing easier. "Life"? I don't know...
I would get the chemical advisory data for the chemistry you are using. I've used Photocolor, Tetenal, Russel, Agfa chemistry - (probably others as well) and I can't find anything super-dangerous in their compositon. I wouldn't drink the stuff, but I don't think these are any more of a concern than black-and-white chemistry, either. NOTE: This statement does NOT apply to Cibachrome P3/ P30 chemistry. That stuff, I WOULD worry about.