Alternative Photographic Processes: Cyanotype, Salt Prints, Platinum and More

Before factory-made silver gelatin paper, photographers coated their own paper with light-sensitive solutions and printed in sunlight. Many of those processes are still practiced, for their color, surface and handmade character. Most are contact processes, so they need a negative the size of the final print.

Why contact printing and large negatives

Most alternative processes are sensitive only to ultraviolet light and far too slow for an enlarger. Prints are made by laying a negative directly on the coated paper under glass and exposing to sunlight or a UV light source. That means either a large format negative, such as 8x10, or an enlarged digital negative printed on transparency film from a scan.

Cyanotype

The cyanotype, invented by Sir John Herschel in 1842, is the easiest place to start. Paper is coated with a mixture of ferric ammonium citrate and potassium ferricyanide, dried in the dark, exposed under UV for several minutes, and developed in plain water. The image is a deep Prussian blue.

Inexpensive kits and pre-coated paper are widely available.
Exposure is judged by eye: the image appears as you expose it.
Prints can be toned with tea or tannic acid toward brown or black.
Cyanotypes also make striking photograms of leaves and objects, no negative needed.

Salt prints

The salt print, developed by William Henry Fox Talbot in the 1830s, is the earliest paper process. Paper is soaked in salt solution, then brushed with silver nitrate to form light-sensitive silver chloride in the fibers. Exposed in sunlight, it prints out a visible image, which is then fixed. Salt prints have soft, warm brown tones and a matte surface. Silver nitrate stains skin and must be handled with gloves.

Van Dyke brown

Van Dyke brown uses ferric ammonium citrate, tartaric acid and silver nitrate together, coated in one step. It gives rich brown prints and is a natural next step after cyanotype for those who want warm tones.

Platinum and palladium

Platinum and palladium prints are made with ferric oxalate, which is light sensitive, and a platinum or palladium salt. After exposure the image is developed and cleared, leaving metallic platinum or palladium embedded in the paper fibers. They have an exceptionally long, delicate tonal scale and are among the most permanent images known. The metals are expensive, so prints are costly to make, but many consider them the most beautiful photographic prints of all.

Lith printing

Lith printing uses ordinary silver gelatin paper, heavily overexposed and developed in very dilute lith developer. The developer works slowly at first and then rushes in the shadows, giving prints with warm, grainy, soft highlights and hard black shadows. The exact moment you pull the print decides the result, so no two are identical.

Wet plate collodion

Wet plate collodion, introduced in 1851, coats a glass or metal plate with collodion, sensitizes it in silver nitrate and exposes it while still wet, then develops it immediately. Glass plates make ambrotypes and negatives; black-lacquered metal plates make tintypes. The process needs a portable darkroom and involves flammable and toxic chemicals, but produces images of startling detail and depth.

Safety

Many alternative process chemicals are hazardous: silver nitrate is corrosive, dichromates used in gum printing are toxic, and collodion is highly flammable. Read the safety data for every chemical, wear gloves and eye protection, ventilate well, and keep a dedicated workspace away from food.