My experience of this is a bit thin… but I can share what I know. Printing requires that a resist is applied onto a plate, onto which the ink is applied. The f

My experience of this is a bit thin… but I can share what I know. Printing requires that a resist is applied onto a plate, onto which the ink is applied. The function of the resist is to accept or reject the ink. This plate is then pressed on to the paper and the ink is thereby applied or not applied depending on the resist. For most of printing history the resist was a binary: acceptance or rejection of the ink. In the case of Etching (Artists = Dore or Rembrandt) the drawing is applied with a metal spike onto wax covered metal sheet, in Silk screen (artists = Toulouse Lau trek) it is applied as a paint resist on a silk-like fabric, in the case of Woodcut (artists = Durer) it is applied as carved grooves on a wooden block. Lithography (invented Aloys Senefelder in 1798) (artists = Daumier) offered something new: nuance. Lithography as I was taught at school was on stone. Uniquely this was applied as a wax crayon on a stone block. This brought the printing medium closer to drawing (freedom of drawn stroke and subtle tones). Stone lithography was wax (resist) on lime stone blocks. This was traditionally a fine art process, slow and expensive. Offset lithography was on cylindrical metal plate. Parallel to this was the evolution of utilitarian color spaces. Used as the starting point was the artist’s Colour space RYB, whereby all visible colors can be synthesized using a base set of no more than three so-called primaries. Derived from this was the CMYK (cyan, magenta, yellow and black) color space. Black was added as the inks that are employed in CMYK have no ‘body’. They are thin and watery. Traditionally they are also of low pigmentation (i.e. cheap). Why cyan, magenta not green and red? That is another story. CMYK and RYB is distinct to red, green and blue (RGB), which defines human vision and projected light. This distinction is the difference between additive and subtractive colors, which is never very effectively explained, but that is yet another story. With all that in place, all that was required was to take a few photos using the appropriate color filters and pass the color-space-seperated result to the printers. each Colour pass was laid down onto the other, the combined result being as bear as damit to the source photo. The issue here was in translating the innate RGB of the camera to the innate CMYK of the printing process. Exact alignment of the separate color passes was an issue. Very fine alignment pins were used to ensure that the different color passes were aligned exactly. The final cookie in the crumble was good quality printing paper, which could accept the inks without dulling the result. The early color plates in classic ‘golden age’ illustrated books where ‘special’. They were protected by thin sheets of non-absorptant paper and printed on special paper stock. Why made offset lithography so significant was that it was the first bridge between photography and printing. Photographs could now be printed. Looked for a good exitstingne]web resource, but found none. Will edit further if anything turns up.