Reversal processing question

[S.Frank]

I have two questions about reverse processing Black and white film. My first pertains to the type of reel/tank to use for this. The instructions in the Photographer's Formulary kit for reverse processing TMAX film state "Do not use stainless steel reels." Does somebody know why this would be? I haven't seen this for other reverse processing instructions--For example, in Steve Anchell's Film Developing Cookbook, he actually advises to use a stainless steel reel when loading the wet film for the second developer, because it is easier to load wet film onto this rather than a plastic type.

My second question regards the procedure for re-exposure of film before the second develpment--these instructions recommend holding the film 12 inches from a 150 watt bulb. I will be using 36 ex rolls of 35 mm for this, so my instinct tells me that I would want to move the film across the light source in either direction in order to assure more even exposure across all of the frames. I suppose a person could use a flourescent tube with similar lumens.

I would certainly appreciate any feedback on these questions.
Thanks

S. Frank

 

[Gerald C Koch]

I have developed color reversal film many times using SS reels without a problem. Leave the film on the reel as it is very delicate at this stage of the process. Hold the reel with its axis toward the light. You should wobble the reel so as to make sure that all of the film is exposed. Then hold the reel from the other side and repeat the process. Thirty to sixty seconds on each side should be more than sufficient. You really can't over expose it. However make sure that the film does not get hot from the heat of the bulb.

 

[Europan]

Stainless steel reels can be corroded at soldering points where the alloy (that makes the steel so-called rust proof) can be partially decomposed. Bleach baths can attack the steel in these spots, and once rust is in it never sleeps any more.

This is the reason why plastic reels are recommended, clear plastic ones for reversing. Replace a plastic reel after 50 processes. Give a fresh plastic reel two complete reversal processes before you use it for serious work. Plasticizers will so become much less influental although only the most critical formulae are sensitive to such. For example Gigabitfilm together with its proprietary chemistry is affected by plasticizers and silver residues that can crouch in porous plastics. Gigabitfilm, on the other hand, is something carried to the extremes, incomparable to most other films.

An incandescent 60-Watt frostet bulb is fine at one to two feet distance to the film. Keep the reel under water all the time while exposing to long-wave light and move it in all directions. This way you continue to dilute chemicals from the clearing bath and prevent marks from droplets.

Wipe the finished film with a double folded clean damp viscose sponge cloth before drying.

 

[johnielvis]

stainless is fine

there have been no reports of problems using stainless for black and white reversal using dichromate--if it's permanganate bleach, then maybe the concern is corrosion--but the tmax direct reversal kit from kodak had permanganate bleach and it doesn't ruin stainless....

re-exposure is not critical at all--if you want to feel good you can clip the film and unreel it from where you intend to dry it...then reel it back together to get a "uniform" exposure--do enough and you get lazy and don't even take it off the reels--the light gets in there--if you can see every portion of the film, so can the light.

just try it and see--address any problems as they come, not BEFORE, or you'll never get anything done.

 

[Gerald C Koch]

I have never seen any signs of corrosion when using stainless steel reels or tanks with either a dichromate or permanganate bleach. The metal is only in contact with the bleach for a very brief period and as a chemist may I say that neither bleach is strong enough to attack SS. The chemical industry routinely uses stainless reaction vessels under far more rigorous reactions. Also I have never seen any reels that are soldered they are welded. So there are no dissimilar metals in contact to affect corrosion. My only concern would be with very cheap reels which may be made of an inferior grade of metal.

There are many types (formulations) for stainless steel. These types are designed for particular conditions. The types used in photography are formulated to resist corrosion from the solutions used.

 

[S.Frank]

reversal processing 101

Thanks for your insight--I employed both methods of re-exposure (in-reel and out-reel) and each seemed as successful. However, I had another issue--the two rolls I processed were left with a splotchiness, especially at the top and bottom edges of the frames--often it would be slightly darker in tone, sometimes it looked actually splattered. I wonder if this is related to the clearing bath step--maybe my agitation was not frequent enough? My bleach step was done with continous agitation. With the second developer I agitated for the first 30 seconds, and 5 seconds every half-minute afterwards. Any thoughts?
Sean