There is no single definable point when the CMYK Process Colour printing was discovered. High fidelity process colour reproduction printing has been a gradual series of technical refinements.

The persons responsible are, however, known.

Printed colour reproduction grew rapidly in popularity in the late nineteenth and early twentieth centuries to today, when (excluding newspapers) the great bulk of all pictorial reproductions is in colour. The basic principles of photomechanical colour reproduction remain the same today as there were in 1900, but there have been many important advances over the years that have led to improved quality and lower costs.

The Colour Process for Colour Reproduction depends on several different factors.

First, is the development of the necessary TRANSPARENT inks. As colour reproduction depends on the subtractive system, the overlap of the process colours cannot work with opaque inks that obscure the under-printed inks and the paper (usually) substrate.

The original pigments used in printing inks were mainly inorganic pigments that had a restricted gamut, and, in some cases, poor transparency. The development of organic pigments increased the available color gamut while still retaining reasonable permanence. The major developments were as follows:



The azo colors for ink manufacture developed between 1899 and 1912. Most Yellow pigments are of this class.



The discovery of the tungstated and molybdeated pigments in about 1914. The best process magentas fall into this class.



The discovery in 1928 of phthalocyanine pigments, which made possible the first really permanent brilliant cyan suitable for process-colour printing.

Other developments that led to use of process-colour printing included the four-colour printing press.

The first recorded use of a four-colour lithographic sheetfed press was by the Traung Label and Lithograph Company of San Francisco, California, during early 1932. This offset press was made by the Harris-Seybold-Potter Company of Cleveland, Ohio (now Harris Graphics). Four-colour web offset presses preceded sheetfed presses. In 1926 the Melbourne, Australia, daily newspaper The Argus installed the German-built Vomag web offset machine that had four perfecting (can print on both sides of the same press sheet) printing units. This press was used to print weekly colour supplements and magazines. The Berlin, Germany company of Messrs Dr. Selle and Company were reported as printing four-colour work by web offset in 1926.

The Cottrell Company reportedly made a four colour common impression cylinder rotary letterpress sheetfed machine about 1912, but the thick letterpress ink films (layers) made wet-on-wet (ink "trapping") process-colour work impractical.

The first recorded three-colour (intaglio) prints were produced on a web machine at Siegburg in 1914. A common impression cylinder was on this machine.

Around the same time, a multiunit Goss intaglio press was installed at The Chicago Tribune. This machine had separate-unit type construction for each colour. However, it is thought that the first successful gravure process four-colour work on a multicolour machine was not produced until the late 1920s or early 1930s, probably on a machine made by the Albert company.

The specific answer to your question is in this entry:

The primary elements [for the CMYK process colour printing we know today] are a magenta red, a yellow and turquoise blue. These three basic hues were brought to perfection by Herbert E. Ives (1882–1953) and represent the minimum "primary" colours which, in combination, will produce a full array of fairly pure intermediates using average pigments. (Ives used the term achlor for magenta, zanth for yellow, and syan for turquoise blue.) Mixtures of magenta and yellow form reds and oranges. Mixtures of yellow and turquoise form greens. Mixtures of magenta and turquoise form purples. These three, in other words , are the fewest that can be employed to produce a satisfactory colour circle. For rich, powerful hues, however, more than three colours becomes essential.

Prior to, and inspiration for, the CMYK dot automated screen colour printing process as a means to create intermediate colours in a print was by manually using points of pigment. The artists that pioneered the effect known as optical mixture were French painters such as Georges Seurat and Paul Signac in 1886. From a distance we cannot clearly perceive the edges of small shapes. Similarly, from a distance a small areas of colour seem to blend into one another and are seen as a mixture rather than as separate hues. The effect occurs in the eye rather than in the pigments. Essentially, pointillism was the immediate precursor to the 4-colour dot screen used by the modern 4-colour process printing

This effect was the focus of experimentation for a group of painters called the pointillists, who theorized that optical mixture would provide a more dynamic expression of colour than the traditional pigment mixing.

A Canadian engraver, Phillip Desbarates, came up with a similar automated process using lines and dots to make halftones images in Montreal, Canada, who discovered the process for printing for the Montreal Star around the same time (1885). Desbaretes later took his concept to the Currier & ives Co. where porcelain china was decorated with scenes using the early "halftone" process with colour materials.

A collision of events near the turn of the 20th century heralded the 4-colour CMYK printing process we have today using transparent inks and dots.

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