Quote Originally Posted by Bob F. View Post
I note that Ilford ship their chemicals in HDPE. Most non-specialist plastic bottles such as fizzy pop and water bottles appear to be PET but they seem to work OK for most things - I've had ID11 for over a year in such bottles. The accordion bottles I have are not marked.

I don't think there is much between plastic and glass for heat transmission. They are both good insulators but are both quite thin in this use.
That's an interesting point actually - in my original maths I used the thermal conductivity of PVC as a typical plastic.

HDPE apparently has a thermal conductivity of approximately 0.5 W/mK, compared to the figures I was using of 0.19 for PVC and 1.05 for glass.

Given that, and the thinner walls of an HDPE bottle compared to glass, I'd say an HDPE bottle will almost certainly conduct the heat as well if not better than a glass bottle. Which would concur with dslater's experience.

Oh, incidentally I don't do C41 but I do E6 - Kodak ship all the E6 chemistry in plastic bottles with the notable exception of colour developer part B, which comes in a brown glass bottle. I keep the mixed chemistry in plastic bottles though, and haven't seen any problems (although I tend to mix it and then use it pretty quickly.)