Salt-Free Salt Print Toned with Himalayan Black Salt

nmp

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MODERATOR's NOTE: This thread evolved as it grew, and it became clear that it would be useful if some of its content were to be moved into a new thread. That work was done and the resulting thread is here: https://www.photrio.com/forum/threads/toning-b-w-slides-with-kala-namak.189593/#post-2508358 . The editing process may have resulted in some minor discontinuities in both threads.

Hi, everyone:

As the title suggests I finally have something to share on my salt-free salt-print process. In the end, after going in circles a bit and struggling with my new printer to get a decent digital negative, I figured it was best to make a baseline process down from which modifications/improvements can be made later.

For background please look at the following threads:

https://www.photrio.com/forum/threads/salt-printing-dark-stain.147621/
https://www.photrio.com/forum/threa...t-makes-a-terrific-toner.148338/#post-1941999

The basic process is really simple.

Materials:

Substrate: Arches Aquarelle Bright White Cold Press.
Negative: Digital Negative, Epson SC-400, Fixxons Transparency Foil
Sensitizer: 10% Silver Nitrate
Rinses: Distilled Water, 0.5% Salt (Sodium Chloride) Solution
Fixer: 15% Sodium Thiosulfate + 0.2% Sodium Carbonate
Hypo Clear: 2% Sodiul Sulfate + 0.2% Sodium Metabisulfate
Toner: 0.5% Himalayan Black Salt

Process:
  1. Rod coat sensitizer, dry 1 hour at room temperature in toaster oven with convection fan turned on.
  2. Expose in homemade UV box using BLB florescent bulbs, 30 min
  3. Distilled water rinse, 2.5 min x 2.
  4. Salt solution rinse, 5 min.
  5. Fix, 5 min.
  6. Tap water rinse, 2 min
  7. Hypo clear, 5 min
  8. Wash, 1 hour
  9. Tone, 6 mins
  10. Wash, ½ hour.
  11. Dry.
Attached is the first and only full image I printed with this process:




:Niranjan.
 
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nmp

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NedL said:
Somehow I completely missed this thread and never would have seen it if you hadn't mentioned it on the alt-photo listserve today.
Well done!
Click to expand...
Thanks, Ned. I think I might have put this post in the wrong place. Should have used the Alternative Processes forum, although the mention of digital negatives might have been a problem there.

:Niranjan.
 
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nmp

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Peter Schrager said:
Looks very nice!@
Click to expand...
Thanks Peter. It seems I need to work a bit to improve my coating/drying process. The sensitizer seems to travel deeper into the paper making it difficult to be cleared out as can be seen from the darker stains in the lower portion of the white border as well as on the step wedge. Perhaps getting the viscosity up by using higher silver nitrate from 10% to 12% or even 15% might help. May be there are some inert additives I can use to the same effect. PVOH or fumed silica come to mind. I wonder if anyone has used those in the sensitizer solution. Those might help in bumping up the Dmax as well. It's decent right now but could be better.

All that and more for the version 2.0...

:Niranjan
 

ced

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Have you tried sizing the paper? Nice print!
 

RalphLambrecht

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is there a formula foe sulphide toning coming out of this thread?
 
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nmp

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RalphLambrecht said:
is there a formula foe sulphide toning coming out of this thread?
Click to expand...

Hi, Ralph: The formula used in this work is simply 0.5% solution of the Black Salt (Kala Namak) in distilled (probably not required) water. I didn't try adding Na carbonate or Na sulfite etc that are normally a part of direct sulfide toners. That is something that can be played around with as a second order experimentation to see their effect on toning rates as well as bleaching tendency.

:Niranjan.
 

mshchem

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Makes me curious what is in the different gourmet salt offerings?? I have only seen black salt one time, in a restaurant. I see a lot of the pink varieties.
Sulfide is horrible stuff, great for toning though.
 
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nmp

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Raghu Kuvempunagar said:
@nmp: there is also the Himalayan pink salt which is supposedly rich in Sulphur.
Click to expand...

Yeah...check the original thread that I linked to where all of these different salts are discussed. The one I used is clearly the so-called Kala Namak. According to this one site, Himalayan Pink salt is a precursor of Kala Namak (they add a bunch of other things that may or may not increase the sulfur content.) Anyway, feel free to try the Pink salt and see if it is active enough for the purpose of toning or may be even better than Kala Namak.

:Niranjan.
 

MattKing

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I've been reading this thread with interest. It is relatively difficult to get sulfide based toners around here, but there is a large community of ex-pats from India in this area, along with lots of suppliers of their food preparation needs.
People from the Punjab region have the highest representation - is it likely that I would find the black salt in business catering to their needs?
FWIW, I would be toning silver gelatin prints - primarily RC - and do have access to the rehalogenating bleach components.
 
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nmp

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Absolutely. It's fairly prominent in Punjabi cuisine. It's one of the main ingredients in the famous Chat Masala. I would be very surprised if you don't find it in your local store. Otherwise, there is always Amazon.

:Niranjan.
 

MattKing

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nmp said:
Otherwise, there is always Amazon.
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Funnily enough, all the Amazon.ca sources I have seen involve shipping at a cost and involving a fair amount of delay from India.
 
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nmp

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MattKing said:
Funnily enough, all the Amazon.ca sources I have seen involve shipping at a cost and involving a fair amount of delay from India.
Click to expand...

How about this one:

https://www.amazon.ca/Rani-Unrefine...ry&sprefix=black+salt+,grocery,63&sr=1-3&th=1

It's chunky, but can be easily ground up in a spice grinder or a few blows of a hammer will suffice. I am guessing since it is available on Prime, it would ship from within Canada.

I would try the local India store first - ask someone to help you get Kala Namak.

:Niranjan.
 

MattKing

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Thanks, I missed that one.
I see I could get a 4 pound jar of it in ground up form from the same site at very reasonable cost.
But that is a lot of salt! Particularly before I've experimented with it.
I'll add it to my Amazon wish list.
And I will try a local Indian food supplier first.
 

NedL

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MattKing said:
And I will try a local Indian food supplier first.
Click to expand...
Try that... I'd be surprised if you can't find kala namak locally. Our regular grocery store has it ( but they do have a display with a couple dozen kinds of salts... )
This thread is making me want to pull it out and play with it again too.
 

MattKing

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If you want a chuckle, read the user reviews on Amazon for Black Salt. It appears that a fair number of people who buy it there aren't aware how a salt that includes sulphur and is likely to produce hydrogen sulfide when used is likely to smell!
 

Raghu Kuvempunagar

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Here is an analysis of the mineral composition of Pink Salt. Sulfur content varies from 1703.97 mg/kg to 33754.34 mg/kg in the samples they tested with the average being 7344.70 mg/kg. In comparison, the white table salt they tested had 431.22 mg/kg of Sulfur.

Regarding the high alkalinity of the Black Salt solution, it seems Sodium sulfide hydrolyzes in aqueous solution as follows:



Dissociation constant of the last two is smaller than that of the second and hence the solution becomes alkaline.
 
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nmp

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Thanks for the links. First one is a treasure trove - didn't think the sulfur content could vary so much.

Regarding alkalinity of the solution, I checked the same for my Kala Namak sample and it is practically unchanged from my tap water used to make the solution, i.e. around 6. So there is no move towards alkaline scale after dissolving the salt (0.5-2%.) I am intrigued that one you have makes such a high pH solution. I wonder if the powdered stuff loses some of its sulfuric content as opposed to the un-ground one that yours seems to be. Of course, this Keya brand could inherently have higher sulfur than the one I have. Or may be it has some added sodium carb/bicarb or something.

Regarding hydrolysis, it fits with the experience of a more intense whiff of H2S gas soon as the salt is added to water.

:Niranjan.

Addendum: Looking closely at Table 3 in the study, it seems the really high (5 figures) sulfur salts are mostly from Australian sources. Himalayan ones vary but within 4 figures with one exception in crystal form greater than 10K.
 
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RalphLambrecht

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That's right; I get it at my local Asian food store.
 
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