How does Kallitype toning "work?"

Out of curiosity I tried looking up how Platinum, Palladium, and gold toning Kallitypes (and other similar processes) work. I wasn't able to find much. I found a few references stating that "more noble metals will replaces less noble metals" in the print during toning, but nothing that seems to state how that works. I know that these metals don't form compounds with metallic silver like sulfur and selenium will. Some literature states that gold will "plate" the silver crystals in silver gelatin prints so how is it different when gold toning a Kallitype? Is this one of those things where it isn't well understood how this works?

Disclaimer... I'm a (retired) bio/organic chemist with a spotty knowledge of inorganic chemistry.

All silver-based image are formed from metallic silver... Ag(0). The different silver-based processes yield different sized particles of Ag(0) which leads to differing tones in the final print. However, the toning of all of these processes is essentially the same.

Toning with noble metals [i.e. gold (Au), platinum (Pt) or palladium (Pt)] involves the following reaction (where X is one of the noble metals)...

Ag(0) + X+ ----> Ag+ + X(0)

In words the metallic silver is oxidized back to silver ions as the noble metal ions are reduced to their metallic form, X(0). This occurs on the surface of the image forming silver particles.

The result is some of the silver ends up back in solution and the X(0) is deposited onto the surface of the remaining Ag(0) particles.

Using your original descriptions "more noble metals will replaces less noble metals" and "gold will "plate" the silver crystals".

Hope this helps.

Thanks for the reply! Yeah that helps and is what I was looking for. Is there a name for this particular type of reaction or would it just be classified as "oxidation?"

cirwin2010 said:

Thanks for the reply! Yeah that helps and is what I was looking for. Is there a name for this particular type of reaction or would it just be classified as "oxidation?"

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This is an oxidation-reduction reaction... often shortened to redox reaction.

Back in school, if you had a chemistry class, you might remember "LEO says GER"... LEO = Loss of Electrons - Oxidation and GER = Gain of Electrons - Oxidation.

An oxidation is always coupled to a reduction. The electrons lost from one species always end up being gained by some other species. The electrons lost in oxidation have to go somewhere!

cirwin2010 said:

Out of curiosity I tried looking up how Platinum, Palladium, and gold toning Kallitypes (and other similar processes) work. I wasn't able to find much. I found a few references stating that "more noble metals will replaces less noble metals" in the print during toning, but nothing that seems to state how that works. I know that these metals don't form compounds with metallic silver like sulfur and selenium will. Some literature states that gold will "plate" the silver crystals in silver gelatin prints so how is it different when gold toning a Kallitype? Is this one of those things where it isn't well understood how this works?

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Have you looked at


There is enough technical info there to challenge anyone

cirwin2010 said:

Is there a name for this particular type of reaction

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In addition to what @fgorga mentions about this being in the scope of redox reactions in chemistry, I've seen this referred to in a photographic context as 'metal replacement toning'. Eg. here: https://en.wikipedia.org/wiki/Photographic_print_toning#Metal_replacement_toning

I have another similar question that one of you smart folks can help me with. In the context of redox reactions, what is the correct order of reactivity of the following elements: Pt, Pd, and Au?


I have read through "Kallitype, Vandyke Brown, and Argyrotype" by Don Nelson. In one of the chapters he has a short mention of double toning Kallitypes with Platinum, Palladium, and gold. He states that Pt and Pd are more noble than Au and will not be replaced by Au. If you tone with Au first then it will be replaced by Pt or Pd.

I tried this with a Kallitype that I first toned with Pd until it stated looking a dark brown in color. I then put it in my gold toner (231) bath after a rinse. This turned the print a blue black color much like if I had only used the gold toner exclusively. I did not get the warm highlights that Don's book suggested I should have been able to achieve.
This lead me down a rabbit hole of trying to understand the reactivity series of metals. Some sources seem to suggest that Pt would more readily give up its electrons than Au. I assume Pt is "more noble" than Pd so I would also assume this to mean that Pd is more reactive than Au. This contradicts the author of my book so I'm looking for clarity. I am also seeing contradictory information online regarding if Pt is more reactive than Au (or vice-versa) hence why I would want to consult someone with a better understand of chemistry than I.

I don't know if the exact answer you are looking for is there, but have you looked at the free book downloads on Dr Mike Wares site?

mikeware.co.uk

As far as "which should be used first", I've seen references to gold toners for platinum prints, which implies that gold should be done before platinum. Presumably that applies to palladium as well.

I'm seeing a few vague referencing online about gold toning platinum/palladium prints. So that is possible? If so I think that proves that the information in the book is incorrect, yes?

revdoc said:

As far as "which should be used first", I've seen references to gold toners for platinum prints, which implies that gold should be done before platinum. Presumably that applies to palladium as well.

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cirwin2010 said:

I'm seeing a few vague referencing online about gold toning platinum/palladium prints. So that is possible? If so I think that proves that the information in the book is incorrect, yes?

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Both of these posts are correct.

The reason, as one might suspect, is in the details of the redox chemistry.

The propensity to donate or accept electrons is measured by the 'standard electrode potential' which is typically measured in volts.

Here are the values for the metals in question

Au -- 1.5
Pt -- 1.19
Pd -- 0.92
Ag -- 0.80

A metal with a higher potential can be used to replace one with a lower potential.

Thus, gold (Au) can be used to tone prints made with any of the other metals under discussion.

Furthermore, if one gold tones a print already toned with platinum (Pt) or palladium (Pd) the gold will replace the Pt/Pd thereby 'undoing' the first toning.

With split toning the devil is in the details, one needs to pay careful attention to both the concentration of the toners, the time prints stay in the toning bath and the temperature if one wants to have reasonably consistent split toning.

Split toning results will depend on the extent of gold toning since the subsequent toning with Pt or Pd will depend on how much residual silver is present after the gold toning.

I may have this backwards but I believe that gold tones from the bottom (shadows) up and platinum from the top down. Here is a kallitype that I split-toned with gold and platinum:

fgorga said:

Both of these posts are correct.

The reason, as one might suspect, is in the details of the redox chemistry.

The propensity to donate or accept electrons is measured by the 'standard electrode potential' which is typically measured in volts.

Here are the values for the metals in question

Au -- 1.5
Pt -- 1.19
Pd -- 0.92
Ag -- 0.80

A metal with a higher potential can be used to replace one with a lower potential.

Thus, gold (Au) can be used to tone prints made with any of the other metals under discussion.

Furthermore, if one gold tones a print already toned with platinum (Pt) or palladium (Pd) the gold will replace the Pt/Pd thereby 'undoing' the first toning.

With split toning the devil is in the details, one needs to pay careful attention to both the concentration of the toners, the time prints stay in the toning bath and the temperature if one wants to have reasonably consistent split toning.

Split toning results will depend on the extent of gold toning since the subsequent toning with Pt or Pd will depend on how much residual silver is present after the gold toning.

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Thanks for clearing that up! Between your explanation and what I witnessed for myself I can conclude that the author of my book got some information backwards. Now whether I can articulate any of this well enough in an email to the author is another question.

Tom Taylor said:

I may have this backwards but I believe that gold tones from the bottom (shadows) up and platinum from the top down. Here is a kallitype that I split-toned with gold and platinum:

View attachment 409005

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Visually, gold tones from the highlights down. This was very apparent when toning some step wedges for calibration purposes. The effect can be quite strong if the print is pulled early when using a "brown" developer with 231 gold toner for Kallitypes. You would get blue-black highlights and brown shadows.

With my particular process, platinum and palladium appear to tone relatively evenly across the print. I cannot pick out if highlights or shadows are effected first.

Tom Taylor said:

gold tones from the bottom (shadows) up and platinum from the top down.

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I've never found a satisfactory theoretical explanation for this, nor have I been able to demonstrate it. Toners affect the metallic image. They don't care at what part of the curve that metal happens to be.

I think what likely happens is that with some toners, we more easily see the change in hue in the highlights, while with other hues, the shadow changes are more apparent at first. This phenomenon then might have found its way into common parlance, confusing the subjective impression with a physical/chemical mechanism. I think the two should not be confused, especially not in the context of this specific question.

koraks said:

I've never found a satisfactory theoretical explanation for this, nor have I been able to demonstrate it. Toners affect the metallic image. They don't care at what part of the curve that metal happens to be.

I think what likely happens is that with some toners, we more easily see the change in hue in the highlights, while with other hues, the shadow changes are more apparent at first. This phenomenon then might have found its way into common parlance, confusing the subjective impression with a physical/chemical mechanism. I think the two should not be confused, especially not in the context of this specific question.

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This is my understanding as well. All areas are effected equally, but depending on the toner (or bleach) certain areas will show color change before others due to the density thus giving the illusion that highlights or shadows are affected first.

Yes, precisely; I can also see how this visual effect can easily be mistaken for a differential rate in physical metal replacement, but as said, I've never seen good empirical or theoretical support for this.

fgorga said:

Both of these posts are correct.

The reason, as one might suspect, is in the details of the redox chemistry.

The propensity to donate or accept electrons is measured by the 'standard electrode potential' which is typically measured in volts.

Here are the values for the metals in question

Au -- 1.5
Pt -- 1.19
Pd -- 0.92
Ag -- 0.80

A metal with a higher potential can be used to replace one with a lower potential.

Thus, gold (Au) can be used to tone prints made with any of the other metals under discussion.

Furthermore, if one gold tones a print already toned with platinum (Pt) or palladium (Pd) the gold will replace the Pt/Pd thereby 'undoing' the first toning.

With split toning the devil is in the details, one needs to pay careful attention to both the concentration of the toners, the time prints stay in the toning bath and the temperature if one wants to have reasonably consistent split toning.

Split toning results will depend on the extent of gold toning since the subsequent toning with Pt or Pd will depend on how much residual silver is present after the gold toning.

Click to expand...

Again, thanks for the information. I reached out to the publisher of the book and did my best to articulate the error. I did a little addition digging to validate the outlined values and used some your verbiage in my reply. The info will be passed along to the editor and I believe they will take it from there.

Seeking information on Palladium toning of Kallitypes. On this page:
Sandy King shows several examples of palladium toned kallitypes. One is warm toned, as I expected, and several are neutral toned. There is no mention in the article of what processing details allow one to achieve one or the other.
I am on the fence re: trying kallitype, and the possibility of choosing warm or neutral after palladium toning would be a significant incentive.
Oh, and I did email Sandy King a week ago; must be a very busy person.

bernard_L said:

Oh, and I did email Sandy King a week ago; must be a very busy person.

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I'm sure he'll respond; he's generally responsive to questions. But it may take some time for him to get to it.

bernard_L said:

Seeking information on Palladium toning of Kallitypes. On this page:

The Kallitype Process – AlternativePhotography.com

www.alternativephotography.com

Sandy King shows several examples of palladium toned kallitypes. One is warm toned, as I expected, and several are neutral toned. There is no mention in the article of what processing details allow one to achieve one or the other.
I am on the fence re: trying kallitype, and the possibility of choosing warm or neutral after palladium toning would be a significant incentive.
Oh, and I did email Sandy King a week ago; must be a very busy person.

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While I may not be Sandy King, I've done some experimentation with my Kallitypes and you may find the results interesting.

TL;DR The developer you use for Kallitypes may influence the final print color after toning. Or more specifically, the color of the print after the development bath will influence the final color of the print after toning.

I am printing on Legion Revere Platinum paper. Once the paper is coated I place it on a drying screen over a tray of room temperature water and partially cover it. I expose the paper when the coating is dry and the paper is slightly damp to the touch. Too damp and I get uneven exposure. I find that this helps the coating to absorb into the paper evenly and seems to help with dmax over leaving the paper too dry. I am also using the following developer. This should be similar or identical to the Kallitype Black developer sold by Bostick & Sullivan.

• Sodium Acetate 100 gm
• water 1 qt
• Tartaric Acid 3 gm

I find that when this developer is mixed fresh, the prints emerging from the developer bath are very brown in color. After a few prints go through the developer, it causes the prints to become very neutral back with high contrast. I don't yet have an explanation for this "ripening" of the developer, but this does appear to influence the final color of the print post toning.


Here are my findings:
-Palladium toning with fresh (brown) developer yeilds notably brown prints once dry.
-Palladium toning with "ripened" (black) developer yeilds neutral blacks once dry (might have the slightest hint of warmth when compared with platinum toned prints).
-Heating the sodium acetate developer influences the print color after development AND palladium toning.
-The hotter the developer the more warm the final print color
-If the developer is too hot OR stays too hot for too long, it can stain the paper or damage the surface.
-Adequately warmed "ripened" sodium acetate developer yeilds a rich brown black print.

My process for heating the developer and developing the prints:
1. pour 550 to 850ml of developer into a one liter pitcher
2. Heat with a Sous Vide until it reaches 110F
3. Quickly pour the heated developer into a 12x16" tray and then add the print and develope for 10 minutes
4. Clear in tetrasodium EDTA for 5-10 minutes
5. Rinse
6. Tone in palladium toner until completion (5-10 minutes depending on strength)
7. Rinse
8. Fix in Sodium Thiosulfate for 2 minutes
9. Rinse for at least 20 minutes
10. Dry on screen face up

Other findings and problems:
-110F seems to be the sweet spot for the above process. Maximizes the brown effect before the paper stains.
-Pour the developer in the try first. Pouring the developer over the print may cause staining or spots to appear.
-Pouring the same amount of developer into a smaller tray (8x10) may also be causing staining. My best guess is that the developer is staying hot for two long as there is less surface area for the developer to cool.
-While I can get results that are consistent enough to be useful with the outlined process, there is still some varience between my prints when it comes to color and dmax. This may be a result of varience in temperature and the state of "ripening" of the developer.
-Replenishing 1:1 "ripened" developer with fresh developer still goes through the "ripening" process.
-Recently replenished developer will create a rust color sediment after the first print or two. This may get worse with heat and small trays. More testing required.
-The sodium acetate developer should be filtered with a coffee after every print or two. A black sedement will form which I believe is silver. This silver can get stuck in the paper fibers and cause staining, especially on the back of the print.
-The trays should be scrubbed clean to remove black sedement and prevent staining.
-Developer temperature did not yield any obvious differences when using platinum toner. Yeilds a neutral gray. More testing may be required.
-Developer temperature may influence the final color of gold toned (231) prints. Room temp may yeild blue black prints. Hot developer may yeild purple to purple pink prints. More testing is required.
-Using citric acid to clear after developing in sodium acetate causes the print to go orange brown. I don't know if I used too much citric acid or if there was some other processing error.
-Some of my prints appear to become slightly less brown after a few days. Maybe fluctuations in air humidity is causing paper fibers to settle? I have no explanation and I could be imagining things.


My personal thoughts:
-The color of the prints after development is a result of the structure and size of the silver particles in the paper. Even though this silver is getting replaced by the palladium I think that how the new metal gets layed down is influenced by that original structure and density.
-This process is a pain and using a different developer (perhaps sodium citrate?) would be far easier if warm prints are the objective.
-Sodium acetate developer and how it "ripens" is annoying to work with for consistant results.
-Vandyke Brown or Argyrotype prints may be easier to work with and give more consistant results (no developer).
-"Ripened" sodium acetate developer at room temp toned in palladium could be a great way to get neutral prints without paying extra for platinum.
-I will be changing my developer or process once I use up my stock of chemestry.

@cirwin2010
Warm thanks for your detailed write-up. Below some remarks and/or requests for clarification.

For context. It seems to me from examples seen online that palladium toning by default results in warm tones. My interest is in obtaining also neutral tones. The emphasis in your write-up seems to be on obtaining warm tones.

cirwin2010 said:

TL;DR

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Be assured I read all you post carefully

cirwin2010 said:

I am printing on Legion Revere Platinum paper. Once the paper is coated I place it on a drying screen over a tray of room temperature water and partially cover it. I expose the paper when the coating is dry and the paper is slightly damp to the touch. Too damp and I get uneven exposure. I find that this helps the coating to absorb into the paper

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I understand that drying the coated paper "just right" may be important. But can that "help the coating to absorb into the paper" since it happens after coating? What did I miss?

cirwin2010 said:

• Sodium Acetate 100 gm
• water 1 qt
• Tartaric Acid 3 gm

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Do you have an ides whether tartaric acid specifically is required, or whether it is there to adjust the pH, and if the latter, to which target value?

cirwin2010 said:

After a few prints go through the developer, it causes the prints to become very neutral back with high contrast.

Click to expand...

I would hope (if the goal is neutral tone) that one can process more neutral prints than the number required/sacrificed for ripening. Sounds a little like Lith printing... And in all cases try to optimize an assortment of warm toned prints and neutral toned ones.

cirwin2010 said:

-Adequately warmed "ripened" sodium acetate developer yeilds a rich brown black print.

Click to expand...

I understand this in your context where warm toned prints are the goal, and you use heating as means to use ripened developer and still obtain warm tones. But then you don't really need to ripen after replenishment?

cirwin2010 said:

using a different developer (perhaps sodium citrate?) would be far easier if warm prints are the objective.

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And indeed that is the prescription of Sandy King in the page that I linked to. Sodium citrate is cheap; why don't you take that issue out of the way for you (warm prints)?

cirwin2010 said:

-"Ripened" sodium acetate developer at room temp toned in palladium could be a great way to get neutral prints without paying extra for platinum.

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Except, from my reading of your notes, this is quirky. Platinum toner is not that much more expensive than Palladium toner; it is purchasing both that gets expensive if one wants to keep the flexibility warm/neutral.

For context. It seems to me from examples seen online that palladium toning by default results in warm tones. My interest is in obtaining also neutral tones. The emphasis in your write-up seems to be on obtaining warm tones.

Click to expand...

Sodium acetate developer definitely can and will give neutral tones with palladium once the developer is "ripened" and the developer is used and room temp. There may be more consistent ways to achieve this, but that is unknown to me at the moment.

cirwin2010 said:

I am printing on Legion Revere Platinum paper. Once the paper is coated I place it on a drying screen over a tray of room temperature water and partially cover it. I expose the paper when the coating is dry and the paper is slightly damp to the touch. Too damp and I get uneven exposure. I find that this helps the coating to absorb into the paper

Click to expand...

I understand that drying the coated paper "just right" may be important. But can that "help the coating to absorb into the paper" since it happens after coating? What did I miss?

Click to expand...

Honestly not sure why it works, but in my case it does. I've read of humidifying the paper first to get the sensitizer to absorb better in dry conditions. My best guess is the extra humidity after coating prevents the coating from drying too fast and allows it to more evenly distribute across the surface. Regardless of the reason, my results have improved since doing this. I know post humidification can be very important for other types of processes and I saw some referencing on forums to others doing this for kallitype. I found that it works and I haven't really tried any further experimentation with it. My recommendation is to try it if you notice unevenness in the development stage.

cirwin2010 said:

• Sodium Acetate 100 gm
• water 1 qt
• Tartaric Acid 3 gm

Click to expand...

Do you have an ides whether tartaric acid specifically is required, or whether it is there to adjust the pH, and if the latter, to which target value?

Click to expand...

I've seen a few variations on the sodium acetate developer formula calling for differing amounts of sodium acetate and tartaric acid. No doubt this influences the result, but I couldn't say why. That question would be best answered by a chemist. Many formulas call for 3g of tartaric acid per liter/quart from what I have seen.

cirwin2010 said:

After a few prints go through the developer, it causes the prints to become very neutral back with high contrast.

Click to expand...

I would hope (if the goal is neutral tone) that one can process more neutral prints than the number required/sacrificed for ripening. Sounds a little like Lith printing... And in all cases try to optimize an assortment of warm toned prints and neutral toned ones.

Click to expand...

I can say that mixing up a liter/quart of developer at a time will allow me to print many more neutral prints over the required sacrifices (lol). I may experiment with mixing up much larger batches to see if that evens out the consistency a bit. And yes, it does remind me of list printing in a way.

cirwin2010 said:

-Adequately warmed "ripened" sodium acetate developer yeilds a rich brown black print.

Click to expand...

I understand this in your context where warm toned prints are the goal, and you use heating as means to use ripened developer and still obtain warm tones. But then you don't really need to ripen after replenishment?

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I may not be understanding your question. I heat the developer before each print. Heating doesn't "ripen" it per say. I just used as a mechanism to obtain warmer prints after the developer "ripens."

cirwin2010 said:

using a different developer (perhaps sodium citrate?) would be far easier if warm prints are the objective.

Click to expand...

Click to expand...

And indeed that is the prescription of Sandy King in the page that I linked to. Sodium citrate is cheap; why don't you take that issue out of the way for you (warm prints)?

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I bought a bunch of ingredients in bulk before I fully realized the faults of my chosen developer. Don't want to let that all go to waste.

cirwin2010 said:

-"Ripened" sodium acetate developer at room temp toned in palladium could be a great way to get neutral prints without paying extra for platinum.

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Except, from my reading of your notes, this is quirky. Platinum toner is not that much more expensive than Palladium toner; it is purchasing both that gets expensive if one wants to keep the flexibility warm/neutral.

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Definitely quirky. And yeah, buying both was probably not my best financial decision

cirwin2010 said:

And yeah, buying both was probably not my best financial decision

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I did not know that. My remark was more about my own potential purchases. And I'm sure in the mid-term you will find images that benefit from the Pt tonality.

Found another mention of sodium acetate as developer. Or maybe that is where you found it also? Assuming the "neutrality" is preserved after Pd toning.

Unit 4 Papers, developers and toners
Besides the sodium citrate developer shown above, several other developers are interesting. Of particular note is the
sodium acetate developer, which, in contrast to all other formulations, produces an almost neutral image tone.

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That is on page 21 of the 44-page document
on Wolfgang Moersch's site.