B&W reversal: Thiocyanate or Thiosulfate

tustel said:

That's what I thought.
Was curious because Stefan's E6 formula has thiocyanate and wondered if I could use it. Apparently no.
Thank you for confirming.



Tried peroxide with no success.

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If you didn't already, you might try this peroxide recipe that some of us here worked on: https://imager.ie/a-better-peroxide-black-and-white-reversal-bleach/

Copper sulfate bleach is another option and the components are readily available most places. Requires household ammonia.

relistan said:

If you didn't already, you might try this peroxide recipe that some of us here worked on: https://imager.ie/a-better-peroxide-black-and-white-reversal-bleach/

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Hydrogen Peroxide 3% 300 mL
EDTA disodium salt 13.8 gr
Sodium Bicarbonate 12.6 gr
Citric acid 11 gr
pH is about 4.5
Bleaching time 7-9 min.

Is this formula correct? Can I make it in 1L volume?

tustel said:

Hydrogen Peroxide 3% 300 mL
EDTA disodium salt 13.8 gr
Sodium Bicarbonate 12.6 gr
Citric acid 11 gr
pH is about 4.5
Bleaching time 7-9 min.

Is this formula correct? Can I make it in 1L volume?

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That looks right. I have not tested it with the disodium salt but those numbers *should* work. They were contributed as equivalents by @Anon Ymous . Make sure your citric acid is very pure, some folks tried with stuff that isn't, and obviously the measurements will be off and so will the pH.

You can make it in any volume you like. I use 300ml because it is enough for a roll of 35mm in most tanks. When experimenting, I would not make a large volume until I was happy that the formula was correct.

pkr1979 said:

Thanks. Im gonna take a walk on the wild side here and make 2 adjustments at once... I'll lower both 1st developer time and rotation speed ;-)

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My Best results so far with Tmax100 was this..

Metol 2gr
Sulfite 60gr
HQ 6gr
S. Carbonate 48gr
P. Bromide 5,6gr
Thiosulfate 12gr
23°C 8:30 mins