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

[koraks]

Yes,exactly. It'll be the silver-thiosulfate complexes that wash out of the fibers with much difficulty.

 

[D_Quinn]

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.

Thanks! I was thinking of trying Hypo for a different look for my ambrotype work but I'll stick with RF then.

 

[D_Quinn]

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)

Thanks for the helpful info! For now, I’m just doing test prints that I’ll discard anyway, so it’s no big deal. But when I create a 'work,' I'll mix a new Hypo solution.

 

[D_Quinn]

I have some questions regarding the chemicals and sensitivity in salt prints.
Please refer to the attached photo.
All three prints were made using silver nitrate solution and sensitizer (ammonium chloride) that were both prepared on September 28. (The washing and fixing times were the same, and no sizing or toning was done.)
The silver nitrate solution is stored in an amber bottle, and the sensitizer in a clear glass bottle, and I applied the chemicals to the paper just before printing.

Left: Printed on October 5, exposure time was 8.5 minutes
Middle: Printed on October 20, exposure time was 8.5 minutes
Right: Printed on October 22, exposure time was 13.6 minutes

When looking at the prints in person, the one on the left seems the most properly exposed.

Questions:

1. Which chemical, silver nitrate or the sensitizer (or both), loses sensitivity over time?
   Although the left and middle prints were exposed for the same amount of time (8.5 minutes), the middle print is clearly lighter.
2. Which chemical, silver nitrate or the sensitizer (or both), results in lower contrast as it ages?
   I gave the right print a longer exposure time to match the density of the left print. The midtones (like the walls) appear about the same, but the right print clearly has less contrast. The blacks are not as deep, the highlights don't stand out as much, and overall, the print looks muddier.

If anyone experienced in salt prints could provide some insight, I would greatly appreciate it.
Thank you!

 

[koraks]

Which chemical, silver nitrate or the sensitizer (or both), loses sensitivity over time?

They're both stable.

How are you exposing your prints; i.e. what kind of light source? Have you verified that your light source is consistent? Note that e.g. LED light sources tend to become less efficient as they heat up (example here), while fluorescent tubes can show the exact opposite effect.

Moreover, differences in humidity of the paper during exposure as well as differences that arise during coating (esp. resulting in a changed ratio of chloride to silver) can explain what you're seeing.

Mind you, I'm hesitant when it comes to using ammonium chloride because of inherent problems with fogging. Sodium chloride is in my view a better choice for salt prints.

 

[D_Quinn]

They're both stable.

Thanks for the comments!

Hmm. Is my understanding correct that a silver nitrate solution or sensitizer that is somewhat old (only a month) will not affect the contrast? Also I store the silver nitrate solution in an amber glass bottle, but it’s not completely lightproof. Is that a problem?

How are you exposing your prints; i.e. what kind of light source? Have you verified that your light source is consistent? Note that e.g. LED light sources tend to become less efficient as they heat up (example here), while fluorescent tubes can show the exact opposite effect.

Moreover, differences in humidity of the paper during exposure as well as differences that arise during coating (esp. resulting in a changed ratio of chloride to silver) can explain what you're seeing.

I'm using the same type of LED as shown on your website (only 1 unit of 150W, 30cm above the paper). However, in the previous photos, the left and middle prints were exposed for the same amount of time (8.5 minutes), but the middle one is clearly lighter. For both, the sensitizer was applied with a brush, and the silver nitrate with a glass rod. Could the lighter result be due to using too little silver nitrate, if I was being a bit stingy with it?

Mind you, I'm hesitant when it comes to using ammonium chloride because of inherent problems with fogging. Sodium chloride is in my view a better choice for salt prints.

Is it okay to use regular sea salt, or should I buy sodium chloride from the pharmacy?

 

[koraks]

Is my understanding correct that a silver nitrate solution or sensitizer that is somewhat old (only a month) will not affect the contrast?

That's correct.

Also I store the silver nitrate solution in an amber glass bottle, but it’s not completely lightproof. Is that a problem?

Silver nitrate by itself does not degrade. It's still best to store it dark and cool. My working stock is in a clear glass bottle and I keep it in a simple closet; nothing special. It lasts indefinitely this way.

Could the lighter result be due to using too little silver nitrate, if I was being a bit stingy with it?

Yes. Variations in the exact amount and ratio of chloride to silver are likely to occur when hand-coating. It's best to work in a very consistent way and carefully measure out the amounts of both the chloride and the silver solutions.
The ratio between silver and chloride has a strong influence on printing speed, contrast and image tone.

Is it okay to use regular sea salt, or should I buy sodium chloride from the pharmacy?

I use sodium chloride from the supermarket; it's best to use the non-iodized kind. The cheapest tends to be the best, at least around here.
People have made very pretty prints with salt literally taken from the sea. In fact, seawater diluted approx. 1+1 with tap water should make a decent salting solution as my own salting solution is 1.6% NaCl and seawater is around 3.5%; my silver nitrate solution is 11% by the way.

 

[D_Quinn]

That's correct.

Silver nitrate by itself does not degrade. It's still best to store it dark and cool. My working stock is in a clear glass bottle and I keep it in a simple closet; nothing special. It lasts indefinitely this way.

Yes, that was what I thought as I store my silver solution for a wet plate in a clear glass bottle.

Yes. Variations in the exact amount and ratio of chloride to silver are likely to occur when hand-coating. It's best to work in a very consistent way and carefully measure out the amounts of both the chloride and the silver solutions.
The ratio between silver and chloride has a strong influence on printing speed, contrast and image tone.

This is something that I never thought of. I wasn't really consistent in terms of the amounts of both solutions.

I use sodium chloride from the supermarket; it's best to use the non-iodized kind. The cheapest tends to be the best, at least around here.
People have made very pretty prints with salt literally taken from the sea. In fact, seawater diluted approx. 1+1 with tap water should make a decent salting solution as my own salting solution is 1.6% NaCl and seawater is around 3.5%; my silver nitrate solution is 11% by the way.

I found a package of salt at home. This is a common salt sold at a regular supermarket. I don't think it is iodized, so it should work fine. Let's see how it goes.

Thanks!!

 

[koraks]

This is something that I never thought of. I wasn't really consistent in terms of the amounts of both solutions.

Then this is most likely the main factor you're running into.
Refer to page 26 of Ellie Young's thesis: https://core.ac.uk/download/pdf/15614798.pdf

Note how low silver:salt ratios result in weak prints.

I found a package of salt at home.

Give it a try; it'll likely work OK. There's a tiny bit of calcium sulfate in there apparently, but I don't expect it'll be enough to pose much of a problem.

Note that when doing salt prints, I always add a drop of 10% citric acid to every ml of silver nitrate. This eliminates fog.
If you haven't done so yet, I'd recommend doing a fogging test that determines whether the whites in your print clear OK. Sensitize a piece of paper and then exposure part of it to an image, while masking another part with an opaque material. Preferably mask an edge so you can see the transition of the sensitized part into unsensitized paper. After processing, the masked area should have cleared to pure paper white with no difference visible between the unsensitized edge of the paper and the masked, sensitized area. If you do see a difference, you have some fog, which ideally should be eliminated.

Many people who make salt prints don't do this fogging test and as a result run into problems with longevity of their prints (due to insufficient rinsing, fixing and washing) or are limited in the tonal scale since their whites are never really white; the prints will always remain a little bland.

Here's a small test print I made a few days ago:

Note that there's a tiny bit of fog along the lower edge on the right half of the print (below the darkest steps of the Stouffer); in this case it's due to exposure through the rubylith masking material I used (given enough exposure, you can actually print through it!), but the white edge around the image itself is a pure paper white with no stain. (The image is a 35mm negative I enlarged to 4x5" xray film and reversal processed; the image border is extremely dense as a result.)
This print was partially gold toned; dmax is around 1.35logD (darkest patch top left). By comparison, untoned Adox MCC112 matte silver gelatin developed in ID62 maxes out at around 1.45logD.

I've said it before, but especially when just starting out, establish a process that enables you to reliably hit the full tonal scale from the deepest feasible black all the way to paper white. Only once you've figured that out, start linearizing your negatives. Optimizing your digital negatives before you've figured out the printing process itself is a waste of time.

 

[D_Quinn]

Note how low silver:salt ratios result in weak prints.

This is super helpful information, thank you as always.
My silver nitrate solution is 11%, and the Ammonium Chloride solution is 2.3%, so there doesn’t seem to be an issue with the chemicals themselves. However, I hadn’t considered applying the same amount of each solution to the paper, which might have caused the variations in tone and contrast in the prints, as you suggested.

The weak contrast in the final print might have been due to the amount of salt solution applied being significantly less than the silver nitrate, which relatively weakened the concentration of the salt.

Initially, I was applying the silver nitrate with a rod (I do it on a flat surface), but it wasn’t spreading evenly, so I switched to a brush. I’ll try to match the amount of silver nitrate and salt more closely this time.

Note that when doing salt prints, I always add a drop of 10% citric acid to every ml of silver nitrate. This eliminates fog.

The citric acid I have is in crystal form. To make a 10% solution, I need to dissolve 10g of citric acid in 100g of water, right?
For example, if I have 50ml of silver nitrate solution (11%), does that mean I should add 50 drops of the citric acid solution?

Here's a small test print I made a few days ago:
View attachment 381551

The gradation is excellent. Is this paper cotton paper? The surface looks relatively smoother than the type of paper that I use. I need to get some new paper as Hahnemühle Platinum Rag is not currently available. I've ordered it though.

I've said it before, but especially when just starting out, establish a process that enables you to reliably hit the full tonal scale from the deepest feasible black all the way to paper white. Only once you've figured that out, start linearizing your negatives. Optimizing your digital negatives before you've figured out the printing process itself is a waste of time.

I am going to receive the Stouffer step wedge soon. When printing just the step wedge, you can’t capture all the tones from black to paper white, can you? What you’re saying is that I should first find the time for the darkest black, and then look for a state where I can see separation from the darkest black to the next gray, correct?

 

[koraks]

My silver nitrate solution is 11%, and the Ammonium Chloride solution is 2.3%

I suspect that for a 1:1 ratio that's a little high on chloride. It's something you should test to see where the optimum is.

The citric acid I have is in crystal form. To make a 10% solution, I need to dissolve 10g of citric acid in 100g of water, right?

Yes, correct.

For example, if I have 50ml of silver nitrate solution (11%), does that mean I should add 50 drops of the citric acid solution?

I only add it just prior to coating to the volume I'll coat. For a small 4x5" print I'll use something like 1ml of silver nitrate (or even a little less) and 1-2 drops of citric acid. I don't think the amount of citric acid is very critical. Small prints like these I brush coat; first with the salt solution (1.6% sodium chloride in my case), then blast dry with a hairdryer, then the silver nitrate + citric acid, blast dry again, and expose + process immediately.

Is this paper cotton paper?

It's a 50% rag, 50% wood-free paper. It's pretty cheap stuff really, but works surprisingly well. I don't think it's sold in Japan, but as always with paper, try a couple of papers and then settle on something you like and that works well. Every paper responds differently to processes like these.

When printing just the step wedge, you can’t capture all the tones from black to paper white, can you?

No, in my experience the tonal scale is around 2.25 or so, which is about 15 visible steps.

What you’re saying is that I should first find the time for the darkest black, and then look for a state where I can see separation from the darkest black to the next gray, correct?

Yes, correct. That would be your base exposure. You should test this with an empty sheet of inkjet transparency/OHP film because you'll always print through that film, too. The film absorbs a little UV; it's usually something like half a stop or so, so it's significant.

 

[fgorga]

@koraks has given you much good advice.

I'll chime in with a few additional things...

First and foremost... there are many paths to success with salted-paper printing (or any alt process) and there are even more paths to failure.

Additionally, there are many variables that affect each process. Some of these are known and some are unknown (or poorly understood). Some of the variables must be tightly controlled, some have a bit of 'wiggle-room'.

Thus, consistency in working methods is critical. Find a path that works for you and use that path (down to the smallest detail) every time.

As for specifics, I agree with @koraks that adding citric acid to the silver solution is very useful. However, as he suggests, mix the silver and citric acid just before coating. If you premix the two components a precipitate forms slowly over time, a complication best avoided.

Personally, I use a 30% (w/v) solution of silver nitrate and a 15% (w/v) solution of citric acid. My citric acid solution also contains a small amount of blue food coloring. (Thanks to Chris Anderson for this tip.) This allows one to see how the coating is being applied. These solutions are mixed together in a 1:1 ratio just before coating. Some papers also require a small amount of 10% (w/v) Tween-20 in the coating mix.

I salt my paper by soaking it in a solution of sodium chloride. I use kosher salt from the grocery store that contains neither iodide nor an anti-caking ingredient. I salt paper in largish batches and store the dried paper in a zip-lock bag. Salted paper is very stable, I have had no trouble using it after storage for months.

Regarding paper, my advice to beginners is to start with one of the papers made specifically for alt process printing (Hahn. Platinum Rag, Bergger Cot, Arches Platine and Revere Platinum are the big ones). Once you can make a good print on one of these you can branch out to other papers, many of which will work and many won't. That said, the large majority of my salted-paper printing these days is done on HPR or Revere Platinum. I only stray from these for specific projects when I want a warm-toned paper or a thin paper.

A good resource for picking paper is Chris Anderson's massive paper table, see: https://www.alternativephotography.com/massive-paper-chart/.

Lastly, I'll put in a plug for Anderson's wonderful book on salted-paper printing, see: https://www.routledge.com/Salted-Pa...mporary-Artists/Anderson/p/book/9781138280229. Lots of good information on both the basics and on the myriad of variations.

 

[D_Quinn]

@koraks
@fgorga
Thanks for all the useful information!

The step wedge finally arrived today, so I'll be testing it this weekend.

Salt printing seems simple and visually easy to get started with, but it also seems to have a lot of depth. If any questions or issues come up (which is very likely), I'll reach out to you again!

 

[D_Quinn]

Based on some information I read somewhere, I currently use a fixing solution by dissolving 25g of Hypo into 200 ml of water, but I’ve come to realize that people often use a more diluted fixing solution. Could you share any formulas that use Hypo, along with approximate fixing times and washing times?

Does using too strong of a fixing solution lead to drawbacks, like the image becoming too light?
(Since I’m just starting out, I haven’t tried gold toning yet.)

Also, if I use Hypo Clear, will it shorten the washing time?

If anyone can help, I’d appreciate it!

 

[koraks]

I can't comment on the 'plain hypo' fixers. I always use C41 color film fixer in a high dilution (1+20 or so) for a couple of minutes.
My experiences with sodium thiosulfate fixers was mostly that it took a long time to completely fix salt prints. I used to fix for 2x 5minutes with a change to fresh fixer halfway through.

I can only offer the suggestion to do your own testing to determine how to fix and wash. It depends a lot on the paper used, too; some fix and wash quicker than others.

 

[fgorga]

I have been following the recommendations in Chris Anderson's book.

Fixer:

150 g sodium thiosulfate & 2 g sodium carbonate per liter, prepared fresh (enough for about a dozen 8x10 prints)

I use two trays for fixer 5 minute per tray

Hypoclear:

10 g sodium sulfite per liter for five minutes (again enough for about a dozen 8x10 prints)

FWIW, I wash salted-paper prints in static (i.e. non-running) water... six changes of water with ten minutes between changes. For small prints I set up six trays and just transfer prints between trays. For larger prints, I use one tray and dump/refill. Slow and probably overkill, but better safe than sorry.

 

[D_Quinn]

Thanks koraks and fgorga for the advice!

 

[D_Quinn]

FWIW, I wash salted-paper prints in static (i.e. non-running) water... six changes of water with ten minutes between changes. For small prints I set up six trays and just transfer prints between trays. For larger prints, I use one tray and dump/refill. Slow and probably overkill, but better safe than sorry.

Watching YouTube videos, I notice people rinsing with water by replacing the water in the tray about three times rather than using running water. Is this to avoid washing away too much silver?

After using Hypo Clear, how long is your typical final rinse time with running water?

Thank you very much.

 

[fgorga]

Watching YouTube videos, I notice people rinsing with water by replacing the water in the tray about three times rather than using running water. Is this to avoid washing away too much silver?

After using Hypo Clear, how long is your typical final rinse time with running water?

Thank you very much.

I don't think that one can over wash salt-paper prints. I have certainly never noticed any change in density upon washing.

I do not have running water in my dim room, so I never wash with running water. I just use the method I described above. Six changes of water in a tray (with occasional rocking) after the hypo clear; ten minutes between changes.

My full processing for salted-paper is as follows...

1 - 5% (w/v) salt
2 - a second tray of 5% salt
3 - water (prints get gold toned after this if I am toning)
4 - 2% sodium carbonate (only necessary after toning a print)
5 - fixer
6 - a second tray of fixer
7 - water
8 - hypo clear

five minutes in each tray / lots of rocking for first two trays then occasional rocking for the rest

wash in water as described above after the hypo clear

 

[D_Quinn]

I don't think that one can over wash salt-paper prints. I have certainly never noticed any change in density upon washing.

I do not have running water in my dim room, so I never wash with running water. I just use the method I described above. Six changes of water in a tray (with occasional rocking) after the hypo clear; ten minutes between changes.

My full processing for salted-paper is as follows...

1 - 5% (w/v) salt
2 - a second tray of 5% salt
3 - water (prints get gold toned after this if I am toning)
4 - 2% sodium carbonate (only necessary after toning a print)
5 - fixer
6 - a second tray of fixer
7 - water
8 - hypo clear

five minutes in each tray / lots of rocking for first two trays then occasional rocking for the rest

wash in water as described above after the hypo clear

Thank you for the detailed explanation! It’s clear and very helpful!

 

[koraks]

Is this to avoid washing away too much silver?

As @fgorga says, it's probably not possible to overwash salt prints, although at some point the paper may disintegrate...People who wash by changing water instead of using running water are probably just limiting their water use. It's sensible, too. I often do it the same way. Sometimes I use running water, with the water being just a trickle. Then leave it for an hour or so.
I never use hypo clear on my salt prints but it may be a perfectly good approach.

 

[D_Quinn]

I only add it just prior to coating to the volume I'll coat. For a small 4x5" print I'll use something like 1ml of silver nitrate (or even a little less) and 1-2 drops of citric acid. I don't think the amount of citric acid is very critical.

Regarding the timing of applying citric acid: In your example above, should I add 1-2 drops of citric acid on top of 1ml of silver nitrate, mixing it on the paper while coating? I tried this earlier, but it didn’t seem to mix well, and it ended up leaving stains.
Would it be OK to mix the citric acid with the salting solution when applying it, instead of with the silver nitrate?

Also, I asked a question about a response you posted in a different thread earlier. If possible, could you respond? I’m very interested in the topic. I’ll post the link here for convenience.

Step wedge image file?

I'm just about to crank up Photoshop and make myself a step wedge to help with my salt and cyanotype printing. There are some nice tutorials on YouTube on how to do this but it will take me a while and I don't enjoy messing with Photoshop. I spend enough time on computers for work. Why can't I...

www.photrio.com

 

[koraks]

In your example above, should I add 1-2 drops of citric acid on top of 1ml of silver nitrate, mixing it on the paper while coating? I tried this earlier, but it didn’t seem to mix well, and it ended up leaving stains.

I add it to the silver nitrate just before coating and mix well. I measure out my silver nitrate + citric acid solution in a small, separate tray or cup and then brush it onto the paper, or use a pipette to drop it against the puddle pusher if that's what I'm using.

I'll have a look at the other thread in a minute.

 

[Tom Taylor]

It is my understanding that citric acid is a preservative so it's not necessary to use it in the sensitizer unless you are planning on delay printing until much later. When I first started salt printing I did use citric it in the sensitizer but in all cases I print right after drying ~ 1.5 hours after I coat and didn't need a preservative and stopped using it. It will precipitate out after a few days but otherwise has no effect.

All of the salt prints shown on my website were fixed in ~1 minute in 10% hypo with either 2mL of household ammonia or 2 gm of sodium carbonate. They look today as good as when I first printed them.

 

[D_Quinn]

I add it to the silver nitrate just before coating and mix well. I measure out my silver nitrate + citric acid solution in a small, separate tray or cup and then brush it onto the paper, or use a pipette to drop it against the puddle pusher if that's what I'm using.

I'll have a look at the other thread in a minute.

Thank you! That makes sense. I see now that if you don't mix in a separate dish, it doesn’t blend properly. I also need to make sure not to use more silver nitrate than necessary!