materials that taint in E-6

[Tony Clarke]

Greetings from a UK newbie. I'm about to try developing Super 8 cine film (Ektachrome 64T) in Kodak Pro E-6, which looked to be straightforward until I picked up a book on Saturday about darkroom technique. It suggested that of the materials used in making darkroom tanks, stainless steel and nylon got a X rather than a tick for exposure to bleach.

Not being used to anything involving a bleach stage (strictly a b/w negative man hitherto) this looks to be alarming. What's the problem here and how significant is it? I should say that the method being tried here is the biggest Jobo tank in a water bath with the film wound on a homebuilt insert made of polypropylene (plumbing pipe) with epoxied-on spacers of some sort of plastic - this just about gets 50' of S8 inside the tank with the useful bonus of limiting liquid inside to 2 litrs plus room for a temperature-stabilising water bath incorporated in the pipe through sealed ends and an epoxied-in screw cap.

 

[Mike Wilde]

the e-6 bleach batch in my basement is Kodak's. It warns against anything brass. There has been no sign of any problems with paterson tanks, or nikkor/kinderman/? stainless steel reels and a no name stainless steel tank. The nice thing with the bleach is that by that stage all of the development action is over, and things can happen under artificial light, so you could peek in and see what is going on.

If concerned, do two runs - one with no film, just to see how the materials in your bobbin hold up to the chemistry, and then the second, with a sacrificed or un-inportant already processed reel threaded onto your bobbin in water to see that the bobbin is up to the physical forces of it acting against the fluids in the tank, with the tank only filled with water. Bath in photo flo, and you can recover the test film.

 

[Stephen Frizza]

I do know that if you have water thats flown through new copper pipes the copper pipes change the water and can contaminate the chemistry, but i dont know the specifics of that issue...

 

[Photo Engineer]

Copper pipes delivering water will generally do no harm.

Copper in contact with the bleach or any of the process can contaminate them. Included in this is Zinc, Tin and Aluminum.

Stainless of grade 308 or 316 are preferred for use.

PE