Total confusion about bleach!??

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norm123

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Hi all
More I read, more confusion I get.
Is there KBr in Farmer's reducer (Part A)? In Anchell book, yes, and Part B is just sodium thiosulfate.

If I just want to bleach highlight to add contrast to my print with no toning, should I use Farmer's reducer (Part A...Pot. ferri. and KBr) alone, or with Part B (sodium thiosulfate)...together or separate baths.

If I want to tone, should I use the same Farmer's Part A (Pot. ferri and KBr) as the bleach and I fix after the toning with a rapid fixer, HCA and wash?

Regards
Norm
 

esearing

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I find . a visit to photographers Formulary tech sheets on their product pages often provide formulas and usage instructions.

The farmers reducer has different mixtures of A +B depending on its intended use. 2:1:5 for a spot reducer or 30:1:169 for whole page reduction.

Their bleach for Thiourea toner is:
Distilled Water (52C/125F) 750 ml
Potassium Ferricyanide 50 g
Potassium Bromide 10 g
Sodium Carbonate, Monohydrate 20 g
Cold Water To Make 1000 ml

see their reducers/bleaches for negatives too.
 

MattKing

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What are you wishing to do with your bleach?
If you only wish to reduce (lighten) an image, you can use a reducing bleach like Farmers reducer. It doesn't require a source of halogens, because you aren't intending to re-develop for tone. Farmer's reducer includes some fixer, because that permits you to see the effect. One should follow the reducer with a full fix and wash.
I find it more useful though to use a re-halogenating bleach like the formula esearing posted. I prefer that because I can use that bleach either for reducing - include and/or follow up with fixer - or as the first step in a two stage toning workflow.
 

john_s

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A précis of some docs I've downloaded and books I've read for adding a bit of sparkle or counteracting inadequate drydown allowance:

Farmer‘s reducer R-4a, which is made up as follows:
Solution A: Potassium Ferricyanide 75g in 1 Litre water (i.e. 7.5% soln.)
Solution B: Sodium Thiosulphate 240g in 1 litre water
100ml A + 100ml B + 1 Litre or 1½ Litre water.

Swiftly slide in dry print. Agitate rapidly 10 – 15 seconds. This is old advice and it is said that modern papers require more dilute treatment and that is my experience with Ilford Multigrade. (This for dull slightly dark prints that have been a bit overexposed under the enlarger, i.e. inadequate drydown allowance. I think I used the reducer about half that strength.)

Also it is said that warm tone papers require much less also. I have used it with Ilford Multigrade Warmtone (which I found to be barely warmtone in ID-78) and maybe it did need a bit less, I can't really remember. What is important is not to leave it too long: be ready to put it in fresh running water fast. You can always put it back for a bit more. Remember that drydown effect still happens at this stage. Also good washing afterwards is essential (thiosulphate).

Also, Very Weak reducer will tend to affect deeper tones as well, so don't try to use it very weak in order to make the timing less critical.
 

alentine

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A précis of some docs I've downloaded and books I've read for adding a bit of sparkle or counteracting inadequate drydown allowance:
Farmer‘s reducer R-4a, which is made up as follows:
Solution A: Potassium Ferricyanide 75g in 1 Litre water (i.e. 7.5% soln.)
Solution B: Sodium Thiosulphate 240g in 1 litre water
100ml A + 100ml B + 1 Litre or 1½ Litre water.
Swiftly slide in dry print. Agitate rapidly 10 – 15 seconds. This is old advice and it is said that modern papers require more dilute treatment and that is my experience with Ilford Multigrade. (This for dull slightly dark prints that have been a bit overexposed under the enlarger, i.e. inadequate drydown allowance. I think I used the reducer about half that strength.)
Also it is said that warm tone papers require much less also. I have used it with Ilford Multigrade Warmtone (which I found to be barely warmtone in ID-78) and maybe it did need a bit less, I can't really remember. What is important is not to leave it too long: be ready to put it in fresh running water fast. You can always put it back for a bit more. Remember that drydown effect still happens at this stage. Also good washing afterwards is essential (thiosulphate).
Also, Very Weak reducer will tend to affect deeper tones as well, so don't try to use it very weak in order to make the timing less critical.
Thanks John. Great post.
I rarely use this exact reducer components, for only local areas.
But is it supposed to leave a faint yellowish color?
Or is it a matter of high concentration?
 
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norm123

norm123

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A précis of some docs I've downloaded and books I've read for adding a bit of sparkle or counteracting inadequate drydown allowance:

Farmer‘s reducer R-4a, which is made up as follows:
Solution A: Potassium Ferricyanide 75g in 1 Litre water (i.e. 7.5% soln.)
Solution B: Sodium Thiosulphate 240g in 1 litre water
100ml A + 100ml B + 1 Litre or 1½ Litre water.

Swiftly slide in dry print. Agitate rapidly 10 – 15 seconds. This is old advice and it is said that modern papers require more dilute treatment and that is my experience with Ilford Multigrade. (This for dull slightly dark prints that have been a bit overexposed under the enlarger, i.e. inadequate drydown allowance. I think I used the reducer about half that strength.)

Also it is said that warm tone papers require much less also. I have used it with Ilford Multigrade Warmtone (which I found to be barely warmtone in ID-78) and maybe it did need a bit less, I can't really remember. What is important is not to leave it too long: be ready to put it in fresh running water fast. You can always put it back for a bit more. Remember that drydown effect still happens at this stage. Also good washing afterwards is essential (thiosulphate).

Also, Very Weak reducer will tend to affect deeper tones as well, so don't try to use it very weak in order to make the timing less critical.
So, there are 2 "Farmer's" formulae....R-4a...and R-4b...one with KBr and one without.
 

Rudeofus

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AFAIK Farmer's reducer was just Potassium Ferricyanide and Sodium Thiosulfate. In this form it can only be used to brighten images, and whatever is gone is gone.

Alternatively one could start with Potassium Ferricyanide and Potassium Bromide, bleach slowly. If image is too dark, continue bleaching. If bleaching is just right, put it in fixer to get rid of bleached silver. If the image becomes too bright, put it back into developer to restore tones. This second approach is somewhat more complex but leaves a lot more room for error.
 

David Lyga

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Here is what I use: read / heed carefully: Two separate solutions:

Bleach = with potassium ferricyanide (PF), grams = mL, so you choose: mix 3 mL PF in wtm 200 mL. That is your bleach solution. If you want a larger quantity, prorate. This solution does not have to be kept airtight in a bottle. It lasts 'forever'.

Fixer = paper strength fixer, unused.

Now, to make a fabulous reducer, mix (minutes before use as, depending upon dilution, it deteriorates when mixed): one part bleach + one part fix + 0 to 10 parts water (depending upon how fast and how much fog there is to remove). Experiment.

Take the print out a little before it is as bright as you want it to be. Of course, you had to make the print a bit darker because you want the final print to be 'correct'. Contrast will be slightly enhanced and highlights will be brighter. - David Lyga
 

Ian Grant

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So, there are 2 "Farmer's" formulae....R-4a...and R-4b...one with KBr and one without.

Neither contain Bromide, R4a is a Cutting Reducer and significantly stronger than R4b which is a Proportional reducer for lightening areas of prints Both are variations of (Ernest) Howard Farmer's reducer devised in 1883. Farmer was the first Head of the Photography Department at Regent Street Polytechnic in London (now the University of Westminster)

Ian
 
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norm123

norm123

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Neither contain Bromide, R4a is a Cutting Reducer and significantly stronger than R4b which is a Proportional reducer for lightening areas of prints Both are variations of (Ernest) Howard Farmer's reducer devised in 1883. Farmer was the first Head of the Photography Department at Regent Street Polytechnic in London (now the University of Westminster)

Ian
 

darkroommike

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If you are just "clearing" or "brightening" highlights you can use just potassium ferricyanide for highlights, the potassium bromide works as a stabilizer/replenisher and then dip the print into the fixer to clear the highlights, paper fixer has sodium (or ammonium) thiosulfate in it. You can use cotton ear bud (Q-Tip), a bit of cotton on a skewer, a brush (no metal ferrules!), or even a tray of bleach. (more for overall lightening).
 
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norm123

norm123

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If you are just "clearing" or "brightening" highlights you can use just potassium ferricyanide for highlights, the potassium bromide works as a stabilizer/replenisher and then dip the print into the fixer to clear the highlights, paper fixer has sodium (or ammonium) thiosulfate in it. You can use cotton ear bud (Q-Tip), a bit of cotton on a skewer, a brush (no metal ferrules!), or even a tray of bleach. (more for overall lightening).
 
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norm123

norm123

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If you are just "clearing" or "brightening" highlights you can use just potassium ferricyanide for highlights, the potassium bromide works as a stabilizer/replenisher and then dip the print into the fixer to clear the highlights, paper fixer has sodium (or ammonium) thiosulfate in it. You can use cotton ear bud (Q-Tip), a bit of cotton on a skewer, a brush (no metal ferrules!), or even a tray of bleach. (more for overall lightening).
It's more clear now.
Thank you
 
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norm123

norm123

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Neither contain Bromide, R4a is a Cutting Reducer and significantly stronger than R4b which is a Proportional reducer for lightening areas of prints Both are variations of (Ernest) Howard Farmer's reducer devised in 1883. Farmer was the first Head of the Photography Department at Regent Street Polytechnic in London (now the University of Westminster)

Ian
Ha! clear now.
 
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