Half-Tone Photoengraving

(Fr.: autotypie; similigravure; similigravure tramée; héliogravure en relief; typogravure; photogravure à demi-teintes; phototypogravure en demi-teintes; photogravure en relief; phototypographie; typophotographie; typophotogravure)

Most photomechanical processes cannot reproduce a full range of tones (“uniform shading” as seen below) from solid black to bright white, unless they are assisted by the use of a device that can break the original image into lines, dots, holes, etc. Here it is important to notice that in the early days of photomechanical printing, i.e., 1820s until late 1890s, the English language often used the term “half-tones” when referring to the “uniform shading” that refers to a smooth or continuous gradation between black and white. Most processes during that period used a random grain or reticulation to reproduce “half-tones” until, in 1893, Max Levy perfected the (non-contact) ruled screen which became the most popular method of producing “half-tones” until the 1950s. From that date, a new contact screen, often referred to as the Kodak Magenta screen, was introduced first for offset lithography and eventually for letterpress printing. Half-tone reproductions produced by these technologies are easily recognizable with the help of a low power magnifying glass (e.g., 10 X) as the familiar pattern of equidistant dots that vary in size from very small to relatively large.

The expression “the half-tone process” during the period 1893 to the beginning of the 21st century normally refers to half-tone letterpress (half-tone photoengraving) or offset lithography. Prior to 1893, half-tones usually referred to what we would properly call continuous tones, i.e., illustrations that are not made from the familiar half-tone dot pattern referred to above. These continuous tone illustrations are usually obtained from an irregular grain or reticulation process. Modern technology has also introduced a new method based on computer generated stochastic screening.

In common parlance the terminology used can be quite confusing. We prefer using half-tone for reproductions made from a device that uses a regular pattern of dots and continuous tone for reproductions that use everything else, i.e., no dots (e.g., woodburytype) or reticulation of gelatin (e.g., collotype).

The first half-tone process to take advantage of a regular screen pattern was described by H.F. Talbot in 1852. In a section of a patent describing “photographic veils,” he writes: “To produce the effect of engraved lines or of uniform shading, the image of a piece of folded gauze, or other suitable material, is impressed upon the gelatin prior to the image of the object required being formed. Plates of zinc or lithographic stones are also readily engraved by this process.”

The mechanical application of powdered resin, as in the aquatint, was used in the earliest days and A.J. Berchtold recommended, as a better way, printing the grain directly onto the photograph to be reproduced, using either a printing plate or block. He also recommended a system where the photograph was perforated with lines or dots from a roller. In a French patent of December 14, 1857, he describes a one-line glass screen in which parallel lines were scratched on an opaque background.

The first half-tone process used in newspapers was the Canadian leggotype, introduced as a means to replace the woodcut, then the only practical method of producing illustrations. In 1877, the brothers Jaffé, in Vienna, produced the first half-tone plates for newspaper printing. Between 1877 and 1880, Stephen Horgan experimented with making half-tones through perforated cardboard. In 1880, his process was perfected and used for the first half-tone reproduction in America. After the appearance on March 4 in The New York Daily Graphic of the now famous “Shantytown Scene,” all newspapers began reproducing photographs.

Half-tone blocks were used in London’s Graphic from 1884 and in the Illustrated London News from 1885 onwards, the methods at first preferred being those of Meisenbach or Boussod Valadon & Cie’s phototype. Lemercier and Petit in Paris, Angerer and Göschl in Vienna and F.E. Ives in Philadelphia also perfected processes giving similar results. One authority says that the most commonly used half-tone screen was due to Frederic E. Ives, who in the winter of 1885-1886 sealed two single-line screens together (thus producing the first cross-line screen), and Max Levy, who, in 1893, perfected the manufacturing process for it.

The modern variation of the half-tone belongs to the planographic group, and has been called offset lithography, photolithography, or photo-litho process. It works on the principle of lithography, where there is no relief on the printing plate, just areas that attract or repel water and greasy ink. (Nadeau, Encyclopedia, p. xxx.).

“Mirth” by Puyo (duotone photoengraving in black and reddish brown giving a cool selenium toned look). Art in Photography, “Special Summer Number of The Studio,” 1905. 103 x 147 mm.