Does the second E6 developer need to be controlled as closely as kodak says? Could it be used at room temp with no ill effects? Assuming it develops to completion, I see no reason why not unless the temperature interferes with the CD somehow...
Yes, to avoid color shifts, it needs to be within 1 degree. There may still be third party E-6 processing kits that work at room temperature, but the results won't be as good as Kodak, run as Kodak requires.
Someone on the flickr forums has stand developed C41 at room temp and it doesn't look too bad (and that's definitely not Kodak recommended!) - who knows about colour shifts though...
With C-41 you can "sorta" correct for off-temperature processing color shifts when you make prints (or scan) if you are not too picky, however a transparency is an end product. Harder to correct for processing flaws.
I know that the first developer must be closely regulated to prevent cross over, but since the second developer develops to completion, I see no reason why I could not use room temp, except slowing the development.
It is diffusion dependant, even if going to completion and so can lead to problems. At low temps, who says that the couplers have the same activity or the DIAR fragments have the same diffusion rate? If they change, the crossover and color shifts take place!
Tetenal once stated that for the first developer 1°C variation would yield 0.1 colour density variation and that Kodak's and theirs 0.3°C max tolerance should not deterr you.
For the first rinse in the Tetenal 3-bath! process the reduced 0.5°C tolerance is stated by Tetenal as crucial as any residue of first developer will be activated in the following high ph CD.
In a magazine test the temperature of the first rinse for the 6-bath process was reduced even down to 20°C without visible effects.
For the colour developer Tetenal stated that minor variation of temperature will have no influence and the time may be between 4 and 8 minutes without visible variation in density. However in an attached overview they at the same time even reduce the max. tolerance from Kodak's 1°C to 0.5°C for their 3-bath process...
Kodak tests show that pH, time and temperature will affect the CD if too low or high for pH, too low or too short for temp and time..... This is due to the reaction rates of couplers which have different kinetic responses to these factors. This leads to changes in contrast, dmax and color balance. Kodak's color darkroom dataguide used to show the effects of all of these on E6. IDK if the new book has them.
My bet is you would see big differences between using the Color Developer at room temp and at 38C. why bother? If you can get the first developer to 38C why not get the Color developer there too? I imagine the Fix could run at room temp if you gave it more time (not Blix or Bleach).
Kodak tests show that pH, time and temperature will affect the CD if too low or high for pH, too low or too short for temp and time..... This is due to the reaction rates of couplers which have different kinetic responses to these factors. This leads to changes in contrast, dmax and color balance. Kodak's color darkroom dataguide used to show the effects of all of these on E6. IDK if the new book has them.