The challenge with Salt Printing

D_Quinn said:

Does this approach make sense?

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As indicated above, this will result in lackluster prints.
Moreover, trying to solve the problem by adjusting the curve can bring the additional problem of posterization in the digital negative, resulting in poor tonality. If you insist on proceeding with inadequate negatives, it's more sensible IMO to reduce exposure time. You won't hit a decent black, of course, but since you don't have sufficient density in your negatives to work at the full tonal scale, you might as well just shorten exposures so that the negatives still make use of the full printable range of the inkjet printer. Mind you, I must emphasize that this will not make matters all that much better - it just prevents even more problems than you're already juggling with.

Given the negatives you can produce, I would strongly suggest moving away from salted paper prints for now and focus on e.g. Van Dyke brown instead. This comes with the additional benefits of shorter exposures, easier coating, faster processing and less propensity towards staining. It's overall an easier process that most importantly requires less density in your negatives. Its peculiar curve, which tends to easily result in blocked shadows (as the process doesn't have the self-masking that salted paper exhibits), can very readily be compensated for by linearizing your digital negatives for the process.

D_Quinn said:

Furthermore, when I attempted Gold toning on the prints made with this method, expecting the blacks to deepen slightly, the result was that the Dmax actually became shallower compared to the untoned print—quite an unexpected outcome

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Maybe a problem with the chemical makeup of your toner; it's hard to say. In general, gold toning will initially make the print more colorful and with less overall density in the initial stages of toning, but the density will build back up and color shift to more neutral as toning proceeds. I can imagine how mixing errors or degradation of toner working stock can produce a toner solution that results in loss of density and overall poor performance. I personally use thiourea gold toner which I mix just prior to use and discard after use.

Other papers may work better, but the fundamental problem of negatives stands in the way of producing quality prints. There's no way around this except from exploring other printing processes.

@koraks
Thank you for your suggestion about Van Dyke Prints. After researching the process a bit, I feel it could work well, especially considering the performance of my printer.

As for salt printing, I’ve been able to achieve fairly consistent results, except for issues with shallow image depth and uneven coating. I believe this experience could also be applied to Van Dyke Prints.

The issue with Dmax (along with stains and unevenness) only started after I began using gold toner. So, I carefully rechecked the manual. It seems I dissolved the sodium tetraborate in water at about 10°C instead of the recommended 38°C—likely a result of my usual laziness... This might have been the cause of the problem.

Additionally, I’ve been researching the Collodio-Chloride Print process and was wondering if it requires high-density negatives like salt prints. I read in a book about wet plate negatives that Collodio-Chloride Prints, unlike salt prints or albumen prints, can be printed using bright ambrotypes without redevelopment or intensification. Based on this, I’m guessing (hoping) that digital negatives for this process might not need to be as dense. What are your thoughts? (if you know anything about the process).

D_Quinn said:

As for salt printing, I’ve been able to achieve fairly consistent results, except for issues with shallow image depth and uneven coating. I believe this experience could also be applied to Van Dyke Prints.

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Van Dyke builds more density with less exposure, and since it's a single-part sensitizer that's actually a solution (instead of the insoluble silver chloride you're pushing around when doing salt prints), it's also much easier to coat with perfect evenness.

D_Quinn said:

It seems I dissolved the sodium tetraborate in water at about 10°C instead of the recommended 38°C

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As long as it dissolved, it doesn't matter at what temperature you did this.

D_Quinn said:

Collodio-Chloride Print process and was wondering if it requires high-density negatives like salt prints

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Yes, similar.

Thanks koraks! Let's see how it goes...

I don't see whether you are using any citric acid in your silver nitrate. If not, adding some should help with the highlight staining - acid acts as a restrainer - resulting in overall increase in the contrast. Conversely, the paper you are using contains alkaline buffer that would act contrary to the acid. Changing the paper to a non-buffered paper such as HPR should help as well in this regard.

:Niranjan.

As it's been pointed out, the correct negative for the process is important. Correct as in density range, Dmax, etc. Also, as nmp mentioned, Citric Acid. I have a 10% solution that I mix in with the Ag solution 1+1, just before coating. Helps greatly to prevent staining. I have a question unrelated to your issue... where are you sourcing your Alt. chems in Japan? I'll be moving back Kyushu) for a few years...

D_Quinn said:

Thank you very much for your valuable comments and advice! They are extremely helpful.

I believe the biggest factor behind not achieving sufficient Dmax lies in my inkjet printer's inability to produce negatives that achieve adequate whiteness in the highlight areas (this is separate from the issue of Gold toning). However, since I currently don't have the budget to purchase a high-quality printer, I plan to settle for a reasonable level of quality with my current printer.


From the perspective of Dmax, I’ve determined that my UV exposure unit achieves the deepest possible black at around 12 minutes of exposure—just short of causing bronzing. However, when I print a step chart negative (not a Stouffer T2115 but a chart created in Photoshop ranging from 0% to 100%) with a 12-minute exposure, while the black areas reach Dmax, the white patch (100% grayscale on the negative) does not achieve paper white on the print (the negative is on Pictorico film). As a workaround, I’ve been adjusting the curve to sacrifice some degree of Dmax while ensuring a reasonable level of whiteness in the highlights.


Does this approach make sense?

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No, not really. You're just going to get a flat looking print, no matter what else you try.

If you are creating negatives that will not have sufficient density to allow for both full Dmax exposure AND retain clean whites, then you're facing a situation where these issues will never be resolved. Starting with a negative that has the right amount of maximum density and higher than normal contrast is paramount in this process. As I said, I could not achieve a good print when using Pictorico negatives made with my Canon printer unless I made two identical negatives and carefully sandwiched them together as one. It was a tedious hack that I abandoned as impractical, and instead went to developing negatives in double strength PMK, which resulted in ideal negatives for this (and other) alt processes.

This would be as good a time as any to point out that exposure time affects the contrast of the final print. If you use longer exposure times, the contrast will increase slightly. If you can find a way to increase the exposure time to 30 minutes, you'll find you're getting a better looking print, with darker blacks and cleaner whites. This is a known technique, often used to get a better print from an inadequate negative.
You might consider working with outdoor light, in a shaded location (or overcast day) and aim the printing frame at the open north sky.

D_Quinn said:

Furthermore, when I attempted Gold toning on the prints made with this method, expecting the blacks to deepen slightly, the result was that the Dmax actually became shallower compared to the untoned print—quite an unexpected outcome

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If the Gold toner you use is suspected of being one of the issues, then try a different recipe. I use the Gold thiocyanate (Gold chloride and Sodium thiocyanate, in separate stock solutions) and it performs extremely well for me. No staining, no loss of Dmax (in fact it increases Dmax, as any Gold toner should) and it's efficient: I mix 100ml of working solution right before I need it, and that 100ml tones one 8x10 print (would tone two 5x7s). Don't overuse Gold toner - it exhausts quite quickly.

But for many reasons stated above, it's important to tone the print before fixing, to avoid formation of compounds that are difficult (or impossible) to wash out of the print. Yes, I know many practitioners tone after fixing, but it's not ideal and those prints may have decreased permanence as a result. But that only matters if YOU think it matters.

D_Quinn said:

I hadn’t considered the impact of paper choice. So far, my tests have been done on Canson sketchbook paper, but I also have Hahnemühle Platinum Rag and plan to test it with that paper as well.

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Your choice of paper is extremely important! If you have Hahnemuhle Platinum Rag available, then switch to that. It's made for this purpose and is an ideal paper for salt. (and Vandyke Brown, and Kallitype, and...)
Alternative papers I use with equivalent results are: Berger COT 320, Revere Platinum Rag, and of course, Arches Platine, which is possibly the best of the four. (and also the most expensive) For a low-cost alt paper, the Revere is quite excellent.

Can you start from scratch and make in-camera negatives to print from? It's going to give you the most beautiful prints - better (IMO) than what Pictorico negs can give you.

retina_restoration said:

I know many practitioners tone after fixing, but it's not ideal and those prints may have decreased permanence as a result.

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I doubt toning after fixing affects permanence much, if at all. I do see how toning before fixing is more effective and prevents any density loss during fixing; AFAIK that's its main appeal.
The toner I use also involves thiourea which I suspect may play a role in the staining that tends to develop rather easily when the toning is done before fixing. Your post reminds me I should try a thiocyanate formula one of these days. I may have some thiocyanate somewhere.

retina_restoration said:

Can you start from scratch and make in-camera negatives to print from? It's going to give you the most beautiful prints - better (IMO) than what Pictorico negs can give you.

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Amen!

Gold toning forms silver chloride as a byproduct. If it stays in the paper, then whatever it will do would presumably change the image over a period of time. No idea to what extent/direction - I have not seen any study. To be absolutely sure, one might have to fix/wash again.

:Niranjan.

Thanks everyone for all the comments and advice!

As I suspected, the lack of density in my digital negatives is causing me to struggle with creating images with strong contrast. For now, I’m thinking of switching to Van Dyke prints.

At the same time, I’m trying to create negatives using the wet plate collodion process. Wet plate negatives can achieve significant density through intensification, so once I get the hang of it, I plan to give salt printing another try.

Andrew O'Neill said:

As it's been pointed out, the correct negative for the process is important. Correct as in density range, Dmax, etc. Also, as nmp mentioned, Citric Acid. I have a 10% solution that I mix in with the Ag solution 1+1, just before coating. Helps greatly to prevent staining. I have a question unrelated to your issue... where are you sourcing your Alt. chems in Japan? I'll be moving back Kyushu) for a few years...

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Hi Andy, great to hear that you'll be in Japan again. Sure, I'll send you a DM with the information.

D_Quinn said:

Hi Andy, great to hear that you'll be in Japan again. Sure, I'll send you a DM with the information.

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Thanks for that!

D_Quinn said:

Wet plate negatives can achieve significant density through intensification, so once I get the hang of it, I plan to give salt printing another try.

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Intensified wet plate negatives work very nicely for salt prints!

koraks said:

Intensified wet plate negatives work very nicely for salt prints!

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Agreed. They are a match made in photo heaven.

retina_restoration said:

Agreed. They are a match made in photo heaven.

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Yours have always been an inspiration to me, that's for sure.

koraks said:

Yours have always been an inspiration to me, that's for sure.

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That’s nice of you to say, thank you.

By the way, what is the ideal Dmax for wet collodion negatives suitable for salt prints? I know that ambrotypes (positive) have a lower density than negatives, but what is the typical Dmax for ambrotypes? I haven't seen many people's plates, so I am curious about the numerical values.

I consider ca. 2.1logD an ideal contrast range in a negative intended for salt printing. It doesn't really matter how the negative is produced; whether it's film, inkjet or glass plate. There can be differences in your personal preference depending on how you perform the salt print process and what kind of end result you're after.

koraks said:

I consider ca. 2.1logD an ideal contrast range in a negative intended for salt printing. It doesn't really matter how the negative is produced; whether it's film, inkjet or glass plate. There can be differences in your personal preference depending on how you perform the salt print process and what kind of end result you're after.

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Thank you! Do you know a rough Dmax for ambrotypes to appear optimal?

D_Quinn said:

Thank you! Do you know a rough Dmax for ambrotypes to appear optimal?

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I think that's the wrong question to be asking, since Ambrotypes are the finished "print" so to speak. There's no need to measure density values - you simply expose and develop to look right, which is something you can easily determine the moment the plate is fixed.

retina_restoration said:

I think that's the wrong question to be asking, since Ambrotypes are the finished "print" so to speak. There's no need to measure density values - you simply expose and develop to look right, which is something you can easily determine the moment the plate is fixed.

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Thanks for the comment. You're absolutely right, but I was just curious about what might be considered a reasonable density for ambrotypes when they are properly exposed and processed. Since I mostly see other people's plates through scanned digital images, it’s hard to compare directly.

D_Quinn said:

Thank you! Do you know a rough Dmax for ambrotypes to appear optimal?

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As @retina_restoration says, transmissive density measurements on an ambrotype make no sense. Firstly, visual evaluation is all that's needed. Secondly, the optical effect is entirely different than in a printing scenario, with the scattering of light on the silver image combined with absorption of light in a dark background being the image-forming principle. So transmissive density isn't relevant to begin with in an ambrotype. Much more relevant is a factor like physical grain size of the silver image.

Having said that, an ambrotype when viewed as a negative will exhibit exceedingly limited transmissive density. I never measured it, but I expect it to be in the order of magnitude of 0.5logD or so. You can deduce from this that making a good negative for salt printing is a fundamentally different activity from making an ambrotype. I think we've talked about intensification before here on the forum; you now understand why I did that routinely for making collodion negatives for salt printing.

koraks said:

As @retina_restoration says, transmissive density measurements on an ambrotype make no sense. Firstly, visual evaluation is all that's needed. Secondly, the optical effect is entirely different than in a printing scenario, with the scattering of light on the silver image combined with absorption of light in a dark background being the image-forming principle. So transmissive density isn't relevant to begin with in an ambrotype. Much more relevant is a factor like physical grain size of the silver image.

Having said that, an ambrotype when viewed as a negative will exhibit exceedingly limited transmissive density. I never measured it, but I expect it to be in the order of magnitude of 0.5logD or so. You can deduce from this that making a good negative for salt printing is a fundamentally different activity from making an ambrotype. I think we've talked about intensification before here on the forum; you now understand why I did that routinely for making collodion negatives for salt printing.

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And as Korak's says, if your ultimate goal is to make a collodion negative for alt print processes, you need to make a very different plate than you would if it were to be a simple Ambrotype: it requires at least 1 stop more exposure, and it must be intensified by something like the copper sulfate bleach + AgNO3 method or by iodine and pyro redevelopment. (FWIW I always had much better luck with the copper sulfate and silver method)

Ambrotypes are strange animals. They work by a kind of optical trickery that replies on having a black backing to create the illusion. By themselves, viewed as a transparency, they are very weak images indeed.

@retina_restoration
Thanks very much for the explanation! I am aware that ambrotypes and negatives are different. I've succeeded in copper intensification using silver and achieved dense negatives that cannot be viewed as ambrotypes because it's too dense!). I should have made some salt prints by that time though.

@koraks
Finally, I've got all the chemicals needed for Vandyke brown printing.
I found your website below super useful. Thank you!

Reading the website, the concentration of the three stock solutions and the number of drops added appear to be almost identical to the proportions in a standard Van Dyke formula. However, it seems that your tartaric acid stock solution is more concentrated (8%) compared to the typical formula (around 4%). Is there a specific reason for this?

retina_restoration said:

(FWIW I always had much better luck with the copper sulfate and silver method)

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Same here! The copper sulfate + silver nitrate intensification process has always worked very well for me. The iodine process...much less so. I never obtained nice and even results that way, and the copper/silver process was also much more effective.

D_Quinn said:

I found your website below super useful. Thank you!

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Ah, thank you! That's an old page I wrote years ago...but I still mix the sensitizer in the same way.

D_Quinn said:

Reading the website, the concentration of the three stock solutions and the number of drops added appear to be almost identical to the proportions in a standard Van Dyke formula. However, it seems that your tartaric acid stock solution is more concentrated (8%) compared to the typical formula (around 4%). Is there a specific reason for this?

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Note that the ratio in droplets in 'my' formula is different from the equal volumetric ratios you find elsewhere. If you calculate the concentrations of each chemical in the sensitizer as mixed together, you'll find that it's more or less the same either way. The main reason for my approach was that I found that the mixed sensitizer had a much shorter lifespan than I had anticipated, while the individual solutions are very stable (the ferric ammonium citrate is liable to developing mold that can be filtered out, though).