Bromide free Ferricyanide bleach?

[Photo Engineer]

In your reference, note the loss in detail using the NaCl bleach. It looks just like a contrast increase due to the scooping out of the highlights.

Just as I have seen.

PE

[Ian Grant]

Except that the results look the WRONG way around, a Chloride bleach gives a yellower colour and LESS contrast compared to a Bromide bleach with the same toner. Which is something I've used commercially when toning & hand colouring images in the 80's and early 90's.

Ian

[Photo Engineer]

I took the photos at face value with the explanation and they matched what I have seen in tone scale. OTOH, I did not compare them for the image color as that can be influenced by the redeveloper and by the paper type.

PE

[Athiril]

Thanks for the quality responses.

I merely ask at the frustration of a kilo of ferricyanide sitting here, and no bromide either sodium or potassium being available to buy it seems.

This is rather frustrating, its difficult to find and get simple common critical chemicals, but I can get potassium nitrate, ammonium nitrate, magnesium, aluminium powder all from the same place in bucket fulls.

In any case, it seems then ferricyanide+chloride would seem to be okay for non-redevelopment negs and colour reversals.


Edit: As per finer grain.. that is to mean to say I could pull the film out to the light, stick it in the tank, develop to maximum density, then give it a ferricyanide+chloride bleach, and re-load the film in the dark and have finer grain and slower film?

At the very least it would be interesting to shoot on a colour silver chloride film.

[Marco B]

Edit: As per finer grain.. that is to mean to say I could pull the film out to the light, stick it in the tank, develop to maximum density, then give it a ferricyanide+chloride bleach, and re-load the film in the dark and have finer grain and slower film?

It seems highly impractical to me compared to switching on your computer to simply buy a package of slow speed film from the net

And I think you would lose a whole bunch of other important film characteristics determined by for example the dye sensitizers and other chemicals added by the manufacturer.

Marco

[Marco B]

In your reference, note the loss in detail using the NaCl bleach. It looks just like a contrast increase due to the scooping out of the highlights.

I have never used a chloride bleach, only the standard (bromide) bleach that came with my sepia toning kit, but that is an absolute huge amount of unwanted bleaching out of the highlights... I have never experienced anything like that with my bromide based bleach, and I am glad I didn't. In fact, I never have to deliberately overprint to keep my highlights. Yes, of course they are lighter because they are brown, but I do see all the detail coming back in the toner.

Marco

[Ian Grant]

Edit: As per finer grain.. that is to mean to say I could pull the film out to the light, stick it in the tank, develop to maximum density, then give it a ferricyanide+chloride bleach, and re-load the film in the dark and have finer grain and slower film?

At the very least it would be interesting to shoot on a colour silver chloride film.

Athril, it doesn't work like that, you'd lose all speed and colour sensitisation, and it would give low contrast.

It's easier to just add 40g/litre Ammonium Chloride to D76/ID-11, it then gives a Super Fine Grain developer but half the film speed & needs twice the dev time, the technique was used by both Kodak & Ilford.

Alternatively add Iodide free NaCl (Common salt) instead that works well too, you'd need to experiment with the amount but 25gm/litre is a good starting point.

Ian

[Athiril]

I've used bleach before colour developer (regular EDTA stuff from Agfa) and the colour is fine, is there a significant difference between a ferricyanide-bromide and ferricyanide-chloride bleach that would remove colour sensitisation?

I've used salt in Rodinal to gain several stops of speed on colour negs as a first developer, which were then fixed, bleached, re-exposed and colour developed, bleached and fixed. Exposing slower than box speed resulted in poor results, box speed to +3 stops faster were quite good though.

I've seen some guys on one of the intensification groups using a similar technique to that except with Microphen and a ferricyanide-bromide bleach, sometimes with a mercury vapor bath before first development.

I dont really have any D-76/ID-11 to try that out with, just Rodinal and Xtol, though I have a stock of phenidone, ascorbic acid, hydroquinine, aminophenol to mix something up.



And its not easier to jump on the computer, b&w film, except GP3 and a few common others is extremely expensive, more so than Velvia, E100G and others.

Reason is, US, Thailand, Korea and China eBay sellers (real shipping costs) dont stock/sell it - which is where I usually get my film from, can get some bargains at $6-7 per roll for most colour stuff in 120.

Freestyle and all the others start at US$40 shipping, the local supplier (about 2500km away) that actually has that kind of film charge about $18 for domestic shipping, and they charge about $13/roll for 120 b&w stuff.

I've pulled colour up to 14 stops when I didnt have NDs via use of first developer and other techniques etc.

[Ian Grant]

If the bleach is just for colour work prior to fixing Salt, NaCl, will work perfectly well.

Ian

[Athiril]

Your 40 g/L of Ammonium Chloride suggestion, is that to concentrate or working solution?