print processes

  • print processes

  • print processes

    Oil print processes

    At the end of the nineteenth century, some photographers rejected the movement towards mass-produced photographic materials and split-second exposure times by seeking new ways to reintroduce manual procedures into their creative process. They developed techniques that allowed them to play down the automatic nature of photography through manual work on the print and interpretation of the image. Oil processes — including oil prints and bromoil prints — were one notable way of doing this. Because they involve working with brushes, they make it possible for photographers to bring artistry to photography in new ways. Oil print processes are based on the fact that water and greasy lithographic ink repel each other. Ink is applied to a gelatin matrix that has absorbed water in proportion to the density of the image.

    Visual on the left: Untitled, Bromoil print on Baryta paper
    © Constance Asseman, 2015


    The oil print

    The principle of oil printing was described by Alphonse Poitevin in 1855. G. E. Rawlins later reintroduced the process, recommending inking the image with a brush so as to be able to control the aspect of different areas of the print. In France, the Pictorialists Constant Puyo and Robert Demachy included a description of the oil process in their book Les procédés d’art en photographie, published in 1906 by the Photo-Club de Paris. To make an oil print, gelatin is applied to a sheet of paper then sensitized using a solution of potassium bichromate. When exposed to light through a negative, the gelatin on the paper reacts with the bichromate and is tanned (hardened) in proportion to the amount of light it receives. This print is then soaked in an aqueous solution and absorbs water. The dense (or dark) areas of the image are hydrophobic, absorbing little, whereas the areas that are less dense (highlights) are hydrophilic, soaking up water; a slight relief or embossed effect can be observed on the surface of the image. This matrix is then inked. The areas that are saturated with water repel the greasy ink while the drier areas accept it. The ink can be applied with a brush, a brayer (roller) or a combination of the two. Because of the freedom of gesture allowed in applying the ink, the image can be interpreted by varying the treatment of different areas. This stage of making the print is a long and delicate process that sometimes involves several layers of ink and requires great dexterity.

    The bromoil process

    A bromoil print combines the artistic aspect of Pictorialist techniques with the gelatin silver bromide process, which marked the start of the industrial era in photography in the late nineteenth century. The composition of the term “bromoil” illustrates the hybrid nature of this type of print: “brom” refers to the gelatin-bromide base used, while “oil” refers to the greasy ink applied with a brush or a brayer to create a visible image. The process was introduced in England in August 1907 by C. Welborne Piper. It was described as a type of oil print that was simpler to make. A gelatin silver print is subjected to a bleaching bath in which the gelatin of the photographic paper is tanned (hardened) in proportion to the density of the silver image — this image being “eliminated” in the same bath. The subsequent steps are the same as those of the creation of a traditional oil print.

    Transfer techniques and commercialization

    Starting in 1911, Robert Demachy suggested the possibility of transferring oil prints onto Japanese or other artist papers using a lithography press. This became an important practice in oil printing.
    “One might say that the oil print is a step, and that the transfer is a completion,” wrote Constant Puyo.¹
    Despite its manual nature, oil printing gave rise to commercial products: inks and stag foot–shaped fitch brushes, sold by James A. Sinclair & Co. of London, and special gelatin silver bromide papers, sold by Wellington, Ilford and Kodak. These products disappeared from supply catalogs in the 1950s, with the decline of the process.

    Glossaire visuel des procédés photographiques
    © ARCP / Mairie de Paris, 2018


    ¹ Constant Puyo, Les procédés aux encres grasses, huile et report (Paris: Pierre Montel, 1923).


Glossary

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