Pre/Post treatment with Ferricyanide or Sodium Sulfide ?

[Daniel Grenier]

I am currently experimenting toning with Potassium Ferricyanide and/or Sodium Sulfide but I am unclear as to what treatment to give the prints in terms of HCA, Perma Wash or Hypo etc.

Should I treat the print the same as if I was selenium toning or should I be using different steps?

Thanks.

 

[nworth]

Potassium ferricyanide is a bleach, not a toner. It is sometimes used to brighten the highlights in a print. A sodium sulfide solution (watch out, the fumes are poisenous and a powerful fogging agent for sensitized materials) will have a weak toning effect on a print all by itself. It is usually used as a two-bath sepia toner. In that case, the first bath is usually a rehalogenating bleach based on ferricyanide and potassium bromide. Once the print has been bleached, it is redeveloped in the sulfide solution to give a rich brown tone.

 

[Stoo Batchelor]

I am currently experimenting toning with Potassium Ferricyanide and/or Sodium Sulfide but I am unclear as to what treatment to give the prints in terms of HCA, Perma Wash or Hypo etc.

Should I treat the print the same as if I was selenium toning or should I be using different steps?

Thanks.

Hi Daniel.

Firstly, I shall recommend a book to you. 'The Master photographers Toning Book' By Tim Rudman. Its a book that's always good to have on the shelf to go back to on many occasions. The Bible of toning!

From my experience of toning, the use of ferri comes in many ways. As you point out, your concerns lie in the washing of the print. If I intend to use Ferri in any way, i.e liquid light, sepia toning etc, I make sure that the print has had a full wash, a minimum of 45 mins with fibre but I always go the full hour. If your unfortunate enough to have a water meter then hypo clear etc can be used to reduce your wash time. Personally, I don't use it, have, but give it up with no problems.

The importance of the wash is that, in my experience, if any trace of fixer is left in the paper, there can be a loss of fine highlight detail, infact it is quite prominent, and does not re-appear when introduced to the toner. Believe it or not, I found this more problematic with R.C papers. Especially if the toner (Thio, etc) is not up to temperature. A quick dunk of the R.C paper in warm water just before the toner helps.

The golden rule for the Ferri Bath, if your bleaching back the whole print, is that what ever its says the dilution is with water on the packet, double it. If marked @ 1-9, mix it at 1-19, or more. It gives you more control over the bleach.

Just for info. At present, I am split toning my prints. Thio (sepia) and selenium. From my stock of ferri (10g of ferri/100ml water) I use 5 to 10 ml in 1ltr of water. The print stays in this for 2 to 5 min with gentle agitation. What this does is only touches the brightest of highlights. Then a quick wash and in to the sepia, again 2 to 5 mins, depending on what effect you want. Then another quick wash and then selenium tone as per normal.

This does two things for me. Firstly, it is giving me a very light touch of the sepia in the highlights, giving a nice split with the selenium, and secondly, and for what reason I don't know, the ilford Warmtone takes better to the selenium, which I use @ 1-9 instead of the 1-5 that I would use with out the slight bleaching back with the ferri.

Hope this helps and have fun

Regards

Stoo

 

[nworth]

Forgot to address your main point. Treat the toned prints similarly to what you do with selenium toning. Rinse, treat with HCA, wash, and dry. Prints just treated with ferricyanide and not toned should be rinsed, re-fixed, rinsed again, treated with HCA, washed and dried.

 

[Daniel Grenier]

Forgot to address your main point. Treat the toned prints similarly to what you do with selenium toning. Rinse, treat with HCA, wash, and dry. Prints just treated with ferricyanide and not toned should be rinsed, re-fixed, rinsed again, treated with HCA, washed and dried.

"Re-fixed" ? Interesting...

I used the term "toning" loosely as Potassium Ferricyanide" is a bleach as you quite correctly pointed out. What I just started "playing" with are fully processed (but not toned) prints that I heavily selenium tone and then lightly soak in P.F. This imparts interesting colors to the prints which can then be soaked in S.S or not depending on the initial "look" obtained in the first two steps. I am still early in this "playing" processs but I do want to retain sound archival properties to the prints whatever combo I end up using.

Thanks for the suggestions.

 

[Ole]

In that case, if you don't fix again the bleached-back parts of the image will "print out" in light. That means that both colour and density will change over time.

You could of course experiment with partial printing-out in sunlight and then fix when it's reached an interesting tone?

Anyway: I recommend sodium thiosulfate fix after this treatment - "rapid" fix has a greater effect on highlight tones.

 

[Mark Layne]

"Re-fixed" ? Interesting...

I used the term "toning" loosely as Potassium Ferricyanide" is a bleach as you quite correctly pointed out. What I just started "playing" with are fully processed (but not toned) prints that I heavily selenium tone and then lightly soak in P.F. This imparts interesting colors to the prints which can then be soaked in S.S or not depending on the initial "look" obtained in the first two steps. I am still early in this "playing" processs but I do want to retain sound archival properties to the prints whatever combo I end up using.

Thanks for the suggestions.

Daniel
The best discussion of this bleach back process I have seen is in 'Edge of Darkness' by Barry Thornton.He suggests printing down the highlights with warm Neutol WA, heavily selenium toning and then bleaching back.
Mark

 

[dancqu]

A sodium sulfide solution (watch out, the fumes
are poisenous and a powerful fogging agent for
sensitized materials) will have a weak toning
effect on a print all by itself.

The fumes you speak of, are those the fumes
which are credited with such an awful smell?
Perhaps hydrogen sulfide?

I only wonder because on more than one occasion
I've mixed up a sodium sulfide solution and not
detected any odor what so ever.

I've pretty much come to the conclusion that
there is nothing to the claim that a sodium sulfide
solution fumes or smells or fogs. Kodak's Sepia Toner
does not mention fume, smell, or fog, nor does it
include any cautions or warnings. Dan

 

[nworth]

The fumes you speak of, are those the fumes
which are credited with such an awful smell?
Perhaps hydrogen sulfide?

I only wonder because on more than one occasion
I've mixed up a sodium sulfide solution and not
detected any odor what so ever.

...

Yes, it's H2S. People vary a lot as to their sensitivity to odors. You may not be able to smell sulfides well (like I can't smell cyanide). Also, H2S paralyzes your sense of smell at high concentrations. In those concentrations it is very dangerous and is more poisonous than cyanide, so be careful.

 

[dancqu]

Yes, it's H2S. People vary a lot as to their
sensitivity to odors. You may not be able to
smell sulfides ...

Hydrogen sulfide. That's the stuff the Gas Company
puts in the line to alert of any leaks. I've had occasion
to sample it's odor; likely a chemistry class
many years ago.

Sodium sulfide is another matter. In solution it is very
alkaline; a long way from being H anything even NaHS.
I suppose I could test my nose by intentionally
acidifying a sulfide solution.

A few darkroom chemicals are rendered odoriferous
when they need not be. Mine is a 100%
odor free darkroom. Dan

 

[nworth]

The gas company generally uses organic disulfides that are even more foul smelling when concentrated. H2S is often a contaminent in oil and gas as it is pumped from the ground, however, and it must be scrubbed out of the crude product before it can be processed or sold.

H2S is such a weak acid that it forms and escapes from Na2S solutions. In water solution, Na2S dissociates into H2S and NaOH, which is why the solution becomes alkaline. The H2S is not particularly soluble, so it escapes. This is true even in fairly alkaline solutions.

 

[dancqu]

H2S is such a weak acid that it forms and escapes
from Na2S solutions. In water solution, Na2S dissociates
into H2S and NaOH, which is why the solution becomes
alkaline. The H2S is not particularly soluble, so it
escapes. This is true even in fairly
alkaline solutions.

You are correct. H2S IS a very weak acid. It's salt,
Na2S, in water solution undergoes hydrolysis; the S
has a great affinity for H and will attach one and much
will attach two leaving H2S in solution. Also left in
solution are the OH radicals; a product of the
hydrolysis. Those radicals give the solution
it's alkaline character.

My source states the solubility of H2S as 2.61 volumes
per volume of water. So, some what more than 0.1 gram
molecular volume of the gas will dissolve in 1 liter of
water; about 4 grams of the gas. That would
derive from 9 to 10 grams of Na2S.

I'll need to refer back. Solutions I've made of Na2S
have perhaps been no stronger than 1%. No trick to
check with fresh, with or with out acidification.
Of course if my nose is gone ... ?? Dan

 

[Ole]

Above 100ppm in air you can't smell it - the nose shuts down in disgust. That also happens to be a seriously dangerous concentration...