Bleach for black and white prints

Melvin J Bramley

Member
Joined
Dec 27, 2021
Messages
511
Location
Canada
Format
35mm
Can I use Kodak fixer, with hardener, and Potassium Cyanide, AKA Farmers reducer, to make a bleach for enhancing the whites in my prints?
Is using bleach more effective than using BTZ for fogged paper?
I have some PC to use up.
 

xkaes

Subscriber
Joined
Mar 25, 2006
Messages
4,798
Location
Colorado
Format
Multi Format
I hope that potassium cyanide is NOT in your Farmer's reducer.
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
53,326
Location
Delta, BC Canada
Format
Medium Format
Decide first whether you want the bleaching to be reversible.
A re-halogenating breach allows you to reverse the process if you think you have gone too far - by exposing the print to light and developing and then fixing it again.
And if you are fine with how much you have bleached it, finish it with fixer.
Farmer's Reducer can't be reversed.
 

DREW WILEY

Member
Joined
Jul 14, 2011
Messages
14,126
Format
8x10 Format
Depends on the paper. Bleached areas in some papers will exhibit a warmer tonal color shift. You need to test for that. Kodak no longer makes Farmer's Reducer. When I ran out I simply bought the Formulary equivalent. But that is a lot stronger, so I had to dilute it way more than they prescribed to get controllable highlights, rather than total bleach-out. And yes, you can reduce dev fog that way too, and obtain cleaner whites on older paper. You have to re-fix, like Matt noted.

The effect of benzotriazole as a development restrainer is somewhat different. It slows down development of the highlights, but also the effective speed of the paper. It also tends to produce an image tone shift toward cooler.

You can of course combine these methods if you wish.
 

koraks

Moderator
Moderator
Joined
Nov 29, 2018
Messages
23,620
Location
Europe
Format
Multi Format
Melvin J Bramley said:
Potassium Cyanide, AKA Farmers reducer
Click to expand...

You mean potassium ferricyanide. Potassium cyanide is still sometimes used for fixing wet plate/collodion photographs, but my personal view is that it has no place in a modern darkroom whatsoever. A slight misstep with that stuff is lethal.

Farmer's reducer is a mixture of potassium ferricyanide and fixer, i.e. sodium or ammonium thiosulfate. Potassium ferricyanide by itself is just the bleach. When working on prints (or indeed, negatives), I prefer to mix potassium ferricyanide with potassium bromide to make a bleach that turns the silver image back into silver bromide (i.e. it's a rehalogenating bleach - it turns the silver back into a silver halogen). This leaves the image in a white/yellowish state which is invisible on paper, but on film it's actually visible. More importantly, if you bleach too far, you can retrieve the image by simply re-developing it in any B&W developer. If the bleaching action is to your liking, you can then proceed to fix the paper/film to make the bleaching permanent; this will remove the bleached out silver bromide part of the image definitively. This approach gives you more control, since you can go back and correct mistakes.

Melvin J Bramley said:
Is using bleach more effective than using BTZ for fogged paper?
Click to expand...

Not necessarily, but bleaching has the benefit that you can do it after the print is done and you're still not happy with it. It also has the benefit that you can apply it in specific places with a brush, cotton pad etc. So overall it gives you more control.

I still find printing on fogged paper a disappointing, demotivating experience, regardless of whatever workarounds are available.
 

pentaxuser

Member
Joined
May 9, 2005
Messages
20,036
Location
Daventry, No
Format
35mm
I have read the above several times and I am still unclear what the benefits are of a rehalogenating bleach over just potassium ferricyanide and then fixer

Thanks

pentaxuser
 

Saganich

Subscriber
Joined
Nov 21, 2004
Messages
1,280
Location
Brooklyn
Format
35mm RF
What Koraks said. I've gone both ways and using the rehalogenating bleach will save your good prints from the dust bin every time.
 

cowanw

Member
Joined
Aug 29, 2006
Messages
2,236
Location
Hamilton, On
Format
Large Format
It has been my experience that assessing the degree of bleaching before fixing can be misleading as the act of fixing can increase the effect of bleaching. I find it necessary to bleach a few seconds then fix, bleach a bit and fix, until it is how I want it.
The ability to redevelop is thus less useful. And redevelopment (especially repeated) can lead to blotchy colour stains.
I find bringing the edges of fogged paper to original white to be magical.
Your mileage will vary!
 

Nicholas Lindan

Advertiser
Advertiser
Joined
Sep 2, 2006
Messages
4,252
Location
Cleveland, Ohio
Format
Multi Format
In my book bleaching is the only practical method of increasing highlight contrast.

I make up a tray of very dilute Farmer's and give the print a 5-10 second immersion, then a rinse in water and return the print to the fixer. Repeat if necessary. To help judge the effect of bleaching, I find it very helpful to have an unbleached print floating in the same tray as the just bleached one so the two can be compared. I have never tried the rehalogenating method, I should.

Another way to increase highlight contrast is adding a bit of P. Bromide to the developer.

I often combine the two methods together.

* * *​

It is a failing of MG papers that increasing highlight contrast in the print exposure is very difficult. The highlights are the last bit of the HD curve to see increasing contrast as the filter grade is increased. To increase the contrast the highlights have to be dodged back in the main exposure and then burned back in with a #5 filter. I have never gotten this to work satisfactorily.

An alternative, that I have never tried, would be to arrange the main exposure so the highlights are pure white and then burn in the highlights individually with a #5 filter.
 

Vaughn

Subscriber
Joined
Dec 13, 2006
Messages
10,130
Location
Humboldt Co.
Format
Large Format
It can get a bit crazy. These are three 7x19 prints that I bleached, painted with dektol, fixed, rebleached, sepia toned, and then repeated in various ways. I was up until 2 or 3 in the morning having fun with these.
I included what one looked like before the punishment I gave them...
 

Attachments

  • 3xSnag.jpg
    392.8 KB · Views: 49
  • SnagRavenHWY101.jpg
    184.4 KB · Views: 48

john_s

Member
Joined
Nov 19, 2002
Messages
2,153
Location
Melbourne, A
Format
Medium Format
This old post by me describes what I learned in a Tim Rudman course I attended. He calls it "sparkle bath" and is just judicious use of Farmer's Reducer. I have used it on large batches of prints that were slightly over exposed. Maybe they turned out better than if I'd just exposed a little less in the first place.

My prints look so good in the wash, and then they dry.

I love how my prints look in the fixer or wash water. I'm currently using glossy RC papers until I get to the FB ones, and when the RC's are wet they are just beautiful. Not necessarily my prints, the look of any print that's exposed properly really shines when it has a film of water on it. Is...
www.photrio.com
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
53,326
Location
Delta, BC Canada
Format
Medium Format
This image only works as a print because of use of localized bleaching.

Brownie Hawkeye handheld in a darkish forest thicket.
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…