Copper sulphate Bleach bath in the reversal process

Dennis · 2006-05-03T11:11:15+00:00

Hallo! Ich hab mich endlich mal aufgerafft, Kodak HIE im Umkehrprozess einzutesten. Nun sind zwei halbe Filme "verbraten", mit dem ja schon von anderen Mate...

Dennis

Hello! I’ve finally got round to trying out Kodak HIE in the reversal process. I’ve now used up two half-rolls, with the result I’m already familiar with from other materials: the emulsion breaks down during the process. I’ve already gained some experience with the reversal process, keep the temperature of all baths and rinses stable at 20°C (with a tolerance of at least 1°C), and know various ‘tricks’... There’s a guide online on how to process HIE in the reversal process. hieslide What’s remarkable about it is that, among other things, it recommends a bleach bath of 1% copper sulphate/2% sulphuric acid. Of course, I’ve always used potassium permanganate/sulphuric acid so far and am currently considering whether to order some copper sulphate and give it a go. What do you think? Has anyone tried it yet? I’m really keen to hear your thoughts on this. Best regards and happy shooting Dennis PS: Foma R-100 looks great with an initial development in Calbe MH-28. I’ll share the details once I’ve fine-tuned the developer dilution and timing.

Gast

The best way to minimise emulsion strike is to prepare the potassium permanganate bleach bath only as strong as is absolutely necessary (the leading edge of the film in 35mm format must no longer show any negative blackening). Incidentally, the intensity of the bleaching is greater with the same amount of raw chemicals if a potassium permanganate stock solution is prepared (which then oxidises slowly). It is likely that, in a fresh preparation, the potassium permanganate and sulphuric acid are more preoccupied with each other than with the film :) At 24°C and 75 rpm rotation, I use 250 ml distilled water, 10 ml 38% sulphuric acid, 250 mg potassium permanganate (using a small digital mini-scale with 0.01 g resolution) and bleach for 3 minutes. The FP4 roll film suffers no damage whatsoever. The same recipe with 500mg of potassium permanganate at 24°C is a sure-fire way to destroy the emulsion. Also important: add 5ml of Tetenal hardener to the fixer (not 10ml, otherwise you’ll have to rinse for an unnecessarily long time again).