The Bromoil process was developed in the early years of the 20th century to enable ‘control’ to be exercised over straight black and white silver gelatin prints. At the turn of the 20th century, pictorialism was considered one of the most beloved and beautiful forms of photography. This painterly artistic approach experienced its decline with the advent of “purist photography”. The critics at the time insisted that photographs should not be manipulated, advice that was thankfully unheeded by many who continued to use everything from filters to household cleaners to enhance their images.
Bromoils are unique in their appearance as the hand of the artist is very evident in every part of the image – due largely to the oil being applied using a brush over the print. In inking the image, the photographer has the artistic control to alter tonal values to enhance the image and may use different colors of oil pigment. Bromoils have very archival characteristics, as the ink is much more stable over time then traditional silver gelatin prints and contemporary digital prints. They are very different in appearance as the ink is physically raised from the print surface – they are sometimes characterized as looking like a charcoal drawing or etching.
“Bromoil is one of the rarest and the most permanent of the photographic printing processes. Basically the silver image is replaced by lithographic ink. The bromoil technique works because the treated gelatin in the photographic paper varies in hardness with the amount of silver removed during bleaching. The artist begins by making a silver bromide (silver gelatin) print by contact or enlargement. The photo paper is developed and fixed as usual and dried. Then the silver image is bleached out. During bleaching, the dense shadow areas create a hard gelatin while the highlights result in soft gelatin with the greys proportional in between. The bleached print or matrix is fixed once more, washed and dried again. Just before applying the lithographic ink, the matrix is soaked in water. The highlight areas soak up water and will reject the ink while the hard shadow areas will readily accept the ink. The greys of the original print accept ink in proportion to the amount of silver bleached out. A special stag foot-shaped brush is charged with a hard ink and the ink is “hopped” on the delicate surface in a series of layers. Every few inkings, the matrix is re-soaked and excess water carefully removed. Ink can be added to darken shadows or hopped with an uncharged brush to clear highlights or lighten shadows. It takes many hours to build up a depth of ink layer by layer to create the desired image.”1
1: excerpt from The Photographic Historical Society of Canada: http://www.phsc.ca/bromoil.html, retrieved March 30, 2012