Jukka,

Maybe start at 39.5 or 40 degrees C, by 3:15 you may be close to 36 or 35.5 but your average temperature will have been good.

Having the exact temp all the way through is tough but I have had good results using this method. The biggest trick is being able to repeat whatever you decide on reliably.

I have also used the one sheet in the small tank in water bath method and it works but the temperature change is still pronounced.

One reason I don't sweat the temp change so much is that I don't have a calibrated thermometer.

Without a calibrated thermometer (which are normally quite expensive) you may be off 2-5 degrees any way, what really matters is good repeatable results.

Quote Originally Posted by Usagi View Post
I have paterson Orbital for sheet film developing. Works fine with B/W where temperature is near ambient temperature (24 degrees celcius), but with C-41 there's no way to keep required temperature. Within only two minutes, the temperature drops from 38 degree celcius to 35 degree celcius