At the close of 2020 I had decided that one of my photographic projects for the new year would be learning to Salt Print.
For those who might be wondering what Salt Prints are, it was a photographic technique invented by William Henry Fox Talbot in 1839. He had been able to make images onto paper using a negative to positive process for a year or so, but at the time was unable to make the image permanent until his friend John Herschel the inventor of ‘hypo’ or Sodium Thiosulphate informed Talbot of his discovery to make the printed out photograph (POP) permanent.
More info: https://en.wikipedia.org/wiki/Salt_print
**Salted paper **is as old as the invention of photography, which by art history standards is a comparatively young art of a mere 180 years. It was the first photography-on-paper process invented and it became the basis of black & white photography as we know it today. A piece of paper is soaked in salted water, dried, and then coated with silver nitrate, exposed in the sun, toned with gold and other precious metals, and what results is a monochrome print of various colors: yellow-browns, peachy-browns, red-browns, lavender-taupes, purple-reds, dramatic aubergines to neutral dusky blue-blacks. The process can be printed on any kind of paper, not to mention fabric, leather, wood, glass, and ivory. Salt has the longest exposure scale of any photographic process. From highest delicate highlights to deepest shadows, all detail is preserved. It is the process to use when wanting to connect to photography’s historical roots.
Having collected the materials required, read numerous online articles and websites about the process, I began to formulate the steps required.
First, I needed a reliable light source, this needs to be UV - preferably the sun, which in NW Scotland is not the most reliable, especially during the short days of winter…! So I built a UV lightbox. Using wood scraps in the workshop, I bought 2x 20w LED Black light bulbs, fittings to mount the bulbs and electric cable to wire it all together. With this done I ordered the chemistry - Silver Nitrate, Sodium Citrate, Citric Acid, Sodium Thiosulphate; ordered extra mixing vessels, ordered coating brushes, ordered paper - Bergger COT320, a 320g double weight fibre paper, ordered Pictorico Transparency Film to make Digital Negatives, then patiently waited for everything to arrive..!
You’ll possibly notice that I did not order any Sodium Chloride (Salt)..! My intention is to use sea-water from Loch Nevis. Initially I made my first tests with some Natural Sea-salt flakes procured from the kitchen cupboard. I am though now using sea-water directly from the loch at 100%, not diluted with distilled water an article on the www.alternativephotography.com/a-dash-of-salt/ suggested.
With all the materials required now on hand, I began reading through the small booklet written by Mike Ware, Making Digital Negatives with an ink-jet printer, distributed by siderotype.com. This part of the process adds the ability of using larger format negatives. Historically these would be acquired through use of a Large Format camera. By using a digital negative - one can use any image that is processed on a computer and output at the size required to the printer.
Calibrating your own printer is perhaps the most time consuming part. And in terms of quality ouput is affected by the type of inks the printer uses. Pigment inks been better than cheaper Dye based inks. My Epson XP-15000 uses dye based ink. What you’re aiming for is a negative that provides density and contrast to enable a range of tones to print onto the sensitised paper. I ended up using the Printer Dialogue to increase contrast and add yellow/red ink to the negative. This blocks some of the UV light and therefore increases tonality at the expence of slightly longer exposures.
It took me a few small prints, and four iterations of the step-wedge to produce what I consider a baseline print output.
To be cont’d.