Film Friday: How to make your own salt prints with 3 ingredients

An example of a salted print made by Markus Hofstätter using his DIY exposure box. Photo: Markus Hofstätter

Developed in the mid-1800s by Henry Fox Talbot, salt printing represents one of the earliest and most consistent means of turning a negative into a positive print using just three primary ingredients: salt, water and silver nitrate.

These days, salted printing is considered a relatively obscure photographic practice, even amongst analog aficionados. Despite this, it’s a process that is deeply grounded in photography’s earliest roots, and one worth taking up yourself if you’d like to better understand and connect with the medium.

To learn a little more about salt prints, we connected with Markus Hofstätter, a photographer, inventor and modern-day alchemist hellbent on enjoying photography’s many non-digital processes. He recently started experimenting with salted prints and even built his own DIY exposure box for printing (though most folks simply use the sun).

Tell me a little bit about the salt print photographic technique. What got you into this alternative process? I know it dates back to the mid-1800s.

Salt printing was used by Mr. Talbot in 1840 with his Calotypes. He used paper negatives back then and after that, it was used with glass negatives from the wet plate process.

I never thought I would get into salt printing, but after shooting Zebra dry plates, I needed to print the negative somehow. I didn’t want to work with scanned negatives and invert them to positives. I needed something in my hand. So I very recently started with salt printing and really started to like it a lot. I want to do a whole series with salt prints soon.

I will soon (after my studio renovation is finished) also do salt prints with self-made wet collodion negatives.

Can you walk me through the basic steps of making a salt print? Obviously, salt is involved, what else?

Hofstätter’s first salt prints were exposed using just the sun, which is the most traditional way to make one. Photo: Markus Hofstätter

You coat a paper (acrylic paper is good) with a salt solution (sea salt is a good start) and let it dry. Afterward, you brush (there are different techniques) a silver nitrate solution on it and also let it dry. Now you put it in a printing frame. You can also use a normal picture frame that doesn’t block UV light, but a printing frame makes life easier because you can look at the print in between the exposures. Now you expose it to UV light (the sun is a great source for that).

After that, you need to wash it, fix it and wash it again to remove the fixer. You can also tone it before fixing. The longer you wash it after fixing it, the longer the print will be stable.

Is a glass negative necessary for making a salt print?

That’s a great question. It’s only one possibility to do salt prints. You also can use normal negatives or print your own negatives on a transparent film. I already created a digital negative for salt printing. I want to do some salt prints from landscapes I captured with my drone. Not so easy to carry a wet plate camera with a drone.

Hofstätter hard at work installing LEDs for his DIY salt print exposure box. He notes, that you definitely do not need to build on to get started in the process. Photo: Markus Hofstätter

What should folks know before trying to make their own salted paper prints? Any warnings or insights from your trials?

Wear gloves and goggles, because the silver nitrate can give you black stains. There is a great tutorial online from my friend Nejc of Zebra Dry Plates.

Once the paper is sensitized, how long do you have to make a print with it?

I only started recently with salt printing, but I put a ready-to-print paper in a light-tight box for two days and did a print with it without any issues. I am sure you can chart the paper with only salt and store it forever.

Will salt prints fade over time?

A gold-toned salt print will be more stable than a print that is not toned. The most important thing is to do a good wash before fixing and also fix it very well, so all silver halides are removed. The silver halides are always sensitive to UV light and will darken on the print if there are still traces left. Washing, fixing, [and] washing [again] is a very important thing. As said, I am just starting, but that is similar to the wet plate process.

You recently made a DIY UV exposure box for creating salt prints. What prompted this? Do folks starting out with the process need one?

For sure you do not need one. The sun is a great source of UV light. For me, it’s a convenient option to print at night. I am kind of a night owl and very busy all the time. I also want to test how prints will turn out if I expose them to very little UV light over a very long time. I read, that this can bring up more details in the dark areas of the print.

Tell me a little bit about some of your design choices for the exposure box. Is there anything you’d do differently?

First of all, I wanted to make it as easy as possible without any soldering. I also wanted to have an option for a timer, so I can “fire and forget” my prints. I got a great question in the comments of my video about the temperature. I tested immediately what happens if you leave the light on for several hours and luckily it was not an issue. At the hottest point, it warmed up to 44°C (∼111°F). I did a second test for about 40 hours and it still did not get any warmer.

I would maybe integrate a small fan into the box (can easily be done on the back). Maybe I will do a kind of update on that. I would still recommend not leaving the box totally unattended for a very long time. My box is in the same room as my 3D printer and close to that, I have a smoke alarm and a camera where I always can check from everywhere what is happening.

For more on alternative processes, is there anyone you recommend our readers follow or check out?

I mentioned already one tutorial. I think there are many great books and tutorials online or even to buy. The best way is always I workshop. I will maybe attend one of these as well because you never stop learning.

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For more of Markus Hofstätter’s work, check out his blog and Patreon.