C-41 bleach for b&w prints

[alkos]

Hi!

Recently I've been successfully using Fuji HUNT X-PRESS C41 (the 5l kit) bleach for b&w prints in 1+5 and 1+10 dilution (based on the working-strength solution for colour), as a 1st bath for thiourea-based sepia or alone for brightening up the whole thing.

As I have no experience with traditional Farmer's, but this bleach gives me quite nice, delicate yellow/orange staining in the mid tones. It dissapears in the fixer with FB papers, but doesn't with RC (all Ilford MGIV) Would it be normal for the Farmer's as well? I have noticed it gives much warmer, almost orange tone when used before the sepia.

The other question is - what kind of bleach it might be? How can I tell easily if it is proportional or not? I am mostly interested in one that eats highligths and leaves shadows in peace ;-)

 

[Photo Engineer]

Be careful with color bleaches that contain ammonia. They will bleach the highlights out of prints and perhaps even some shadow detail. The bleach contents should be on the bottle. There are several different types in use.

PE

 

[alkos]

"They will bleach the highlights out of prints"

Well, that is what I use them for ;-)

 

[Photo Engineer]

See the rest of that quote. It may not leave the shadow detail in peace, as you put it!

PE

 

[alkos]

Yep, but which one does it then? Any c-41 without the ammonia?

 

[Photo Engineer]

Color bleaches are not intended for B&W materials as a general rule, but all Sodium Ferric EDTA bleaches would work if there was Sodium Bromide present. If a color bleach contains Sodium Chloride, then it would have an effect similar to having an Ammonium bleach.

The best bleach for this purpose is a Ferricyanide / Sodium Bromide rehal bleach normally used before toning or redevelopment steps.

PE

 

[alkos]

Thanks, I'll try to get MSDS for the one I have and check whats inside

 

[Anon Ymous]

The best bleach for this purpose is a Ferricyanide / Sodium Bromide rehal bleach normally used before toning or redevelopment steps.

PE

A bit off topic, but why does every recipe uses Potassium Bromide and none Chloride?

 

[Photo Engineer]

Chloride will dissolve highlight and shadow detail to some extent and therefore distort the tone scale that you may wish to preserve.

PE

 

[Anon Ymous]

You mean something like blur a sharp line? Actually dissolving grains of silver and spreading them?

 

[Photo Engineer]

Chloride in a bleach can turn it into a weak blix. It will dissolve silver grains but not spread them.

PE

 

[Anon Ymous]

Oh, got it. Thank you!

 

[PVia]

As long as we're at it:

Re: toning of prints...What's the advantage of adding KBr to a pot ferri bleach solution? Why not just pot ferri alone?

 

[Photo Engineer]

The idea is to re-form Silver Bromide so you can re-develop. Otherwise, you either have something that cannot redevelop, or you dissolve away the Silver completely.

PE

 

[PVia]

Thanks, PE...always wondered about that, because many times I've just used pot ferri and then went on to tone (thiocarbamide).