Questions about Blurriness, Sizing, and Fixer Deterioration in Salt Prints

D_Quinn · Oct 5, 2024

Recently, I started making salt prints by contact printing from digital negatives. The attached images are the results. For the sensitizer, I am only using ammonium chloride and distilled water. I plan first to understand salt printing with digital negatives and then challenge myself with printing from wet plate negatives.

About the blurriness (A.jpg)
In the digital negative used, all three people are in focus, but in the print, the face and upper body of the adult woman on the right are blurry. However, her hands do not appear to be out of focus. I applied silver nitrate using a rod, but since it didn't cover the paper completely in one pass, I went over some areas multiple times with the rod. Could this method of application be the cause of the blurriness?

Sharpness difference with sizing (no images attached)
In a different print, I tried applying gelatin sizing to the same paper, expecting sharper results. However, it turned out less sharp than the print without gelatin sizing. Is it possible that sizing could reduce sharpness?

Fixer deterioration (B.jpg)
In the image I attached, the print on the right was fixed on September 30, and the other on the left was fixed on October 5 (today). I haven't used gold toning yet, but there is a noticeable color difference. The fixer (hypo) was made on September 30 and has been used continuously. I’ve processed 11 salt prints, 4x5 inches and 5x7 inches, using 200ml of fixer. Could the color difference be caused by the fixer weakening over time?

I would greatly appreciate any comments from those with experience.

Thank you!

koraks · Oct 5, 2024

D_Quinn said:
Could this method of application be the cause of the blurriness?

No. The problem is poor contact between the negative and the printing paper, combined with a non-collimated light source. Step one is to review your contact printing frame and ensure it works well. A plain picture frame with some clamps generally doesn't cut it.

D_Quinn said:
Is it possible that sizing could reduce sharpness?

Well...sharpness is a difficult concept. However, to cut a very long story short, what you're looking at here is just some variation due to the poor contact problem pointed out above.

D_Quinn said:
Could the color difference be caused by the fixer weakening over time?

Yes, but to me, the print on the left looks like it was likely better processed than the one on the right. The one on the right shows substantial highlight staining, likely due to inadequate washing before fixing, inadequate fixing and/or inadequate washing after fixing. Salt prints take time and care to process properly!

Start by fixing the contact frame issue.
Then ensure to make some prints in which you mask part of the sensitized area on the paper along the edges. This allows you to see how much staining you get. A properly processed salt print leaves absolutely no stain on the paper - there should be no difference at all between the sensitized, unexposed paper and the unsensitized paper.

A final note on contrast and maximum density: salt prints are kind of slow. You get the best result if you expose for the amount of time it takes to get a good, solid black (or very dark brown) after the print is fully processed and dried (ignore how it looks during processing; it goes off in all directions). Once you've established that exposure time, you'll have to adjust the contrast of your negative so that you can print the full tonal scale from black to paper white.

Do not be tempted to start with the negative and then adjust the exposure so you just get paper white. The result is virtually always weak prints with poor contrast and low maximum density. Going by your examples, I think you can expose for about half a stop more, maybe a full stop. But you'll have to then work on getting a suitable negative to match the process.

I'd also suggest to work on getting the printing process right first, only then start worrying about linearization of the digital negatives. In my experience it works best if you start by printing a known standard step tablet like a Stouffer; I personally like the T2115 because it's small enough to easily include on the coated area somewhere, and it's fairly cheap. I don't know what's available easily in Japan; I'm sure there are local equivalents.

D_Quinn · Oct 6, 2024

koraks said:
No. The problem is poor contact between the negative and the printing paper, combined with a non-collimated light source. Step one is to review your contact printing frame and ensure it works well. A plain picture frame with some clamps generally doesn't cut it.

Well...sharpness is a difficult concept. However, to cut a very long story short, what you're looking at here is just some variation due to the poor contact problem pointed out above.

Yes, but to me, the print on the left looks like it was likely better processed than the one on the right. The one on the right shows substantial highlight staining, likely due to inadequate washing before fixing, inadequate fixing and/or inadequate washing after fixing. Salt prints take time and care to process properly!

Start by fixing the contact frame issue.
Then ensure to make some prints in which you mask part of the sensitized area on the paper along the edges. This allows you to see how much staining you get. A properly processed salt print leaves absolutely no stain on the paper - there should be no difference at all between the sensitized, unexposed paper and the unsensitized paper.

A final note on contrast and maximum density: salt prints are kind of slow. You get the best result if you expose for the amount of time it takes to get a good, solid black (or very dark brown) after the print is fully processed and dried (ignore how it looks during processing; it goes off in all directions). Once you've established that exposure time, you'll have to adjust the contrast of your negative so that you can print the full tonal scale from black to paper white.

Do not be tempted to start with the negative and then adjust the exposure so you just get paper white. The result is virtually always weak prints with poor contrast and low maximum density. Going by your examples, I think you can expose for about half a stop more, maybe a full stop. But you'll have to then work on getting a suitable negative to match the process.

I'd also suggest to work on getting the printing process right first, only then start worrying about linearization of the digital negatives. In my experience it works best if you start by printing a known standard step tablet like a Stouffer; I personally like the T2115 because it's small enough to easily include on the coated area somewhere, and it's fairly cheap. I don't know what's available easily in Japan; I'm sure there are local equivalents.

Thank you for your helpful answers and suggestions!!
As you mentioned, I was using a picture frame. I had placed thick paper between the negative and the backing board, and it seemed that the negative was in close contact with the glass, but perhaps the pressure was insufficient.
I don’t currently have a contact printing frame, but I believe the attached image is the kind of frame you are referring to, right?

In my original post, the print on the left, I washed it for about 5 minutes before fixing, after developing it. About the print on the right, the washing time was shorter than for the left one. That might have also contributed to the color difference.
I’d like to get a contact printing frame, and once I can make better prints, I’d like to try gold toning as well.

I’ve read somewhere that if toning is not done, the print will fade over time.
Even if I store the print in a place without exposure to UV light (like in a box, for example), will it still fade without toning?

If you know anything about this, please let me know. Thank you!

koraks · Oct 6, 2024

D_Quinn said:
the attached image is the kind of frame you are referring to

Yes, that's the kind that's often used and in general works well!

D_Quinn said:
the washing time was shorter

Yes, that's what I expected. While the shorter wash time might give an initially appealing print, in the long run the highlights can become even muddier.

D_Quinn said:
I’ve read somewhere that if toning is not done, the print will fade over time.

No, that's not necessarily true, but a salt print needs to be fixed and washed thoroughly, and it'll remain quite sensitive to external influences. However, stored properly, an untonrd but properly processed salt print can have a long (possibly indefinitely) lifetime. Gold toning does help making it more stable against fading, but yellowing of highlights can still occur if the print wasn't fixed and washed properly. So toning by itself is also only a partial solution.

Andrew O'Neill · Oct 6, 2024

The sharpness issue is due to poor contact between negative and paper, as pointed out already. I don't bother with those printing frames. Instead, I use a heavy piece of plate glass, that gets placed directly on top of the neg/paper sandwich. It works up to my 14x17 contacts. Go to a glass shop and have one cut to size (with corners and edges sanded!) I had this done when I lived in Japan for my 8x10 contacts. But... If I were using the sun as my main UV light source, then I would probably consider getting a contact printing frame...or making one. There is a lot more Sun in Kyushu, than here in Vancouver, BC!
I don't bother sizing the papers that I use... Hahnemuhle, and Revere.
Don't overuse fixer. It's cheap and easy to mix up.
Use a hypo clearing agent. You can mix from scratch (sodium sulfite).
Wash well.
When I lived in Japan, I wasn't into Alt. processes, so I don't know what challenges there are there for practitioners. I was doing gel/silver, in my tiny little darkroom. Cheers and good luck!

andy

koraks · Oct 6, 2024

Andrew O'Neill said:
If I were using the sun as my main UV light source, then I would probably consider getting a contact printing frame...or making one.

The funny thing is that the sun (at least direct sunlight) is highly collimated and as a result, the requirements on perfect contact between negative and printing paper are more lax. The more diffuse the light source, the better the contact needs to be.

D_Quinn · Oct 6, 2024

koraks said:
Yes, that's the kind that's often used and in general works well!

Yes, that's what I expected. While the shorter wash time might give an initially appealing print, in the long run the highlights can become even muddier.

No, that's not necessarily true, but a salt print needs to be fixed and washed thoroughly, and it'll remain quite sensitive to external influences. However, stored properly, an untonrd but properly processed salt print can have a long (possibly indefinitely) lifetime. Gold toning does help making it more stable against fading, but yellowing of highlights can still occur if the print wasn't fixed and washed properly. So toning by itself is also only a partial solution.

In the first place, is the fading of salt prints caused by ultraviolet light? If silver is affected by hydrogen sulfide, I think it would turn black.

Come to think of it, wet plate collodion (positive/negative) and tintypes are coated with gum sandarac or acrylic varnish, and this is meant to protect the silver from oxidation or discoloration caused by hydrogen sulfide, right?

For paper prints like salt prints, since the substrate is paper, does that mean varnishing would be meaningless?

D_Quinn · Oct 6, 2024

Andrew O'Neill said:
The sharpness issue is due to poor contact between negative and paper, as pointed out already. I don't bother with those printing frames. Instead, I use a heavy piece of plate glass, that gets placed directly on top of the neg/paper sandwich. It works up to my 14x17 contacts. Go to a glass shop and have one cut to size (with corners and edges sanded!) I had this done when I lived in Japan for my 8x10 contacts. But... If I were using the sun as my main UV light source, then I would probably consider getting a contact printing frame...or making one. There is a lot more Sun in Kyushu, than here in Vancouver, BC!
I don't bother sizing the papers that I use... Hahnemuhle, and Revere.
Don't overuse fixer. It's cheap and easy to mix up.
Use a hypo clearing agent. You can mix from scratch (sodium sulfite).
Wash well.
When I lived in Japan, I wasn't into Alt. processes, so I don't know what challenges there are there for practitioners. I was doing gel/silver, in my tiny little darkroom. Cheers and good luck!

andy

アンドリューさん
Thanks for the suggestions!
Actually I've already ordered the contact print frame.
I learned from your salt print video! In Japan, it’s tough because alternative materials aren't as easily available as in North America! Haha.

Andrew O'Neill · Oct 6, 2024

D_Quinn said:
アンドリューさん
Thanks for the suggestions!
Actually I've already ordered the contact print frame.
I learned from your salt print video! In Japan, it’s tough because alternative materials aren't as easily available as in North America! Haha.

I thought so! It was a bit of a challenge sourcing chemicals for scratch made developers, especially pyro/catechol staining developers. I had to have stuff shipped over, ending up at Japan Customs where they would sit...and sit. Even vitamin C crystals! I lived there from '90 to 2002. Go back almost every Summer. Planning to head over in April, and stay a few months. Eventually splitting my time here (Canada Summer) and there (Japan Autumn -Spring). I never got used to Japan Summers! No thank you! Cheers! Just call me アンディー！よろしく！

koraks · Oct 7, 2024

D_Quinn said:
In the first place, is the fading of salt prints caused by ultraviolet light? If silver is affected by hydrogen sulfide, I think it would turn black.

I suspect radicals are the main concern, but I'm not sure. And yes, sulfur compounds would result in conversion to sulver sulfide. It'll be brown in the case of a salt print, but high-density areas may turn black. Salt prints consists of super fine particulate silver; much smaller than the silver grains in a silver gelatin emulsion.

D_Quinn said:
Come to think of it, wet plate collodion (positive/negative) and tintypes are coated with gum sandarac or acrylic varnish, and this is meant to protect the silver from oxidation or discoloration caused by hydrogen sulfide, right?

The varnish does indeed offer chemical as well as mechanical protection. In a typical silver gelatin emulsion (film, paper), the gelatin also does a pretty good job sealing off the silver image from outside influences.

D_Quinn said:
For paper prints like salt prints, since the substrate is paper, does that mean varnishing would be meaningless?

It'll help some; e.g. waxing a print may do something, especially if the wax penetrates the paper base. And it's of course conceivable to seal both sides of the print; front & back. Aesthetic considerations may stand in the way of this though.

D_Quinn · Oct 7, 2024

koraks said:
I suspect radicals are the main concern, but I'm not sure. And yes, sulfur compounds would result in conversion to sulver sulfide. It'll be brown in the case of a salt print, but high-density areas may turn black. Salt prints consists of super fine particulate silver; much smaller than the silver grains in a silver gelatin emulsion.

The varnish does indeed offer chemical as well as mechanical protection. In a typical silver gelatin emulsion (film, paper), the gelatin also does a pretty good job sealing off the silver image from outside influences.

It'll help some; e.g. waxing a print may do something, especially if the wax penetrates the paper base. And it's of course conceivable to seal both sides of the print; front & back. Aesthetic considerations may stand in the way of this though.

Thanks for the answers, koraks
Now I can't wait to make some salt prints with the contact print frame I bought. I hope the sharpness issue gets resolved so I can focus more on achieving good tonality and density.
Do you make albmen prints also?

D_Quinn · Oct 7, 2024

Andrew O'Neill said:
I thought so! It was a bit of a challenge sourcing chemicals for scratch made developers, especially pyro/catechol staining developers. I had to have stuff shipped over, ending up at Japan Customs where they would sit...and sit. Even vitamin C crystals! I lived there from '90 to 2002. Go back almost every Summer. Planning to head over in April, and stay a few months. Eventually splitting my time here (Canada Summer) and there (Japan Autumn -Spring). I never got used to Japan Summers! No thank you! Cheers! Just call me アンディー！よろしく！

Good to hear from people who have lived in Japan! Indeed, last summer's heat was insane. I think Japan will soon be considered a tropical country 笑

Thanks again, アンディ, for all the YouTube videos. They are super informative.

koraks · Oct 7, 2024

D_Quinn said:
Do you make albmen prints also?

I've tried a couple of times and made a handful passable prints. Beyond that - no. And the albumen layer was pretty thin on the ones I made, so they ended up more like salt prints on a sized paper (with sort of an eggshell gloss) than the glossy albumen prints people like Osterman make. Maybe, one day!

Andrew O'Neill · Oct 7, 2024

D_Quinn, out of curiosity, what paper are you using?

D_Quinn · Oct 7, 2024

Andrew O'Neill said:
D_Quinn, out of curiosity, what paper are you using?

I had a bit of trouble finding the papers recommended by people overseas in the Japanese market. I used the Monval Canson watercolor paper.
https://www.gazaihanbai.jp/products/detail/product_id/49464.html

To be honest, the texture is too coarse for me, so I’d like to try something smoother. I’m thinking of trying Hahnemühle, as it seems popular for alternative photographic processes. If you know of any suitable paper available in Japan, I’d appreciate it if you could share the info.

D_Quinn · Oct 7, 2024

koraks said:
I've tried a couple of times and made a handful passable prints. Beyond that - no. And the albumen layer was pretty thin on the ones I made, so they ended up more like salt prints on a sized paper (with sort of an eggshell gloss) than the glossy albumen prints people like Osterman make. Maybe, one day!

Thanks. I’ll definitely try making some albumen prints once I can achieve a reasonable quality with salt printing. I assume I get a bit of more contrast with albumen printing.

Andrew O'Neill · Oct 7, 2024

D_Quinn said:
I had a bit of trouble finding the papers recommended by people overseas in the Japanese market. I used the Monval Canson watercolor paper.
https://www.gazaihanbai.jp/products/detail/product_id/49464.html

To be honest, the texture is too coarse for me, so I’d like to try something smoother. I’m thinking of trying Hahnemühle, as it seems popular for alternative photographic processes. If you know of any suitable paper available in Japan, I’d appreciate it if you could share the info.

The only papers I've seen practitioners use in Japan, were those hand made, expensive, thin papers. I really think it would be cheaper just to bring in a 25 sheet pack of 8x10 Hahnemuhle Platinum Rag or Revere Platinum. I settled on the latter, as it's a bit cheaper, and gorgeous. I use it for Kallitypes, Salt, Cyanotypes, Gums, and Carbon Transfer.

koraks · Oct 8, 2024

D_Quinn said:
I assume I get a bit of more contrast with albumen printing.

I think native contrast of albumen is supposed to be a little higher than salted paper, yes. But you can get really punchy prints with salted paper as well - it's a matter of having the required contrast in the negative!
There's of course the difference in surface, with an untreated salt print being matte and albumen being glossy. This greatly contributes to the apparent contrast as well. You could finish a salt print by waxing it, which will make it look more crisp. I've used generic furniture wax for this purpose, but the classic approach is a mixture of beeswax and lavender oil (which also smells a lot nicer).

The main reason I never really dove into albumen prints is that I pretty quickly concluded that the only way to get good results, is by sensitizing the albumen paper on top of a silver nitrate bath. At that point, I had just gotten out of collodion because I was kind of done with having that silver nitrate bath around, which was costly and left horrible stains all over the place. I didn't want to go all over that again, so left it at salt prints and went back to plain silver gelatin for more glossy prints.

D_Quinn · Oct 8, 2024

Andrew O'Neill said:
The only papers I've seen practitioners use in Japan, were those hand made, expensive, thin papers. I really think it would be cheaper just to bring in a 25 sheet pack of 8x10 Hahnemuhle Platinum Rag or Revere Platinum. I settled on the latter, as it's a bit cheaper, and gorgeous. I use it for Kallitypes, Salt, Cyanotypes, Gums, and Carbon Transfer.

Thanks!
Unfortunately, I don’t see any place in Japan that sells Revere Platinum. I’m supposed to get 8x10 Hahnemuhle Platinum Rag paper soon. Let’s see how I like it.

D_Quinn · Oct 8, 2024

koraks said:
You could finish a salt print by waxing it, which will make it look more crisp. I've used generic furniture wax for this purpose, but the classic approach is a mixture of beeswax and lavender oil (which also smells a lot nicer).

Yes, I saw a couple of videos showing how to apply wax on the salt print.
It looks like it adds some contrast (deepens black), and I would like to try that out.
I assume you were using something like the one below. Does it give the print a yellowish cast to it?

koraks said:
The main reason I never really dove into albumen prints is that I pretty quickly concluded that the only way to get good results, is by sensitizing the albumen paper on top of a silver nitrate bath.

Good to know this information. I was thinking about whether I could use a rod to apply silver nitrate and achieve a good coating. Then I need to redesign my working space for a silver nitrate tray.

I know you don’t do wet plate photography at the moment, but when you were doing it, did you use KCN for the fixing bath or just hypo?

koraks · Oct 8, 2024

D_Quinn said:
I assume you were using something like the one below.

Sort of, yeah. This was a greasy kind, a bit like ointment. It didn't change the white of the paper much, if at all.

D_Quinn said:
I was thinking about whether I could use a rod to apply silver nitrate and achieve a good coating

That's what I tried, but it was a mess. Either it was uneven, or some of the albumen would be picked up by the coating rod - or both.

D_Quinn said:
did you use KCN for the fixing bath or just hypo?

Initially plain hypo (sodium thiosulfate), later normal rapid fixer. That worked best as it cleared the plates really fast. I never say any benefit to the plain hypo; it's just slooooooooooow.

retina_restoration · Oct 8, 2024

If you can get Revere Platinum, that's a very good paper for salt print making. Bergger COT 320 is also excellent.

About fixer: I do not re-use fixer when fixing salt prints! Make it fresh every time and do not re-use it. (I use a recipe for Sodium thiosulfate, not rapid fix)

Andrew O'Neill · Oct 8, 2024

@D_Quinn, you'll be very happy with Hahnemuhle. It's an excellent paper.

koraks · Oct 8, 2024

retina_restoration said:
About fixer: I do not re-use fixer when fixing salt prints!

Probably a good idea, too. Neither do I, btw. I imagine staining can become a problem really fast.

retina_restoration · Oct 8, 2024

koraks said:
Probably a good idea, too. Neither do I, btw. I imagine staining can become a problem really fast.

The problem with re-using fixer on salt prints is that there will be staining appear months or years later. You won't likely see a problem until long after the print was finished.

Questions about Blurriness, Sizing, and Fixer Deterioration in Salt Prints

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