This image has not been colour corrected, while the others have. The caption for the image. The two pages of accompanying text by Aron Hamburger, Managing Director of the Polychromide Company. Gravure is rarely used in the late nineties, except for special purposes. It involves photochemical etching of microscopic crevices in steel cylinders.
Ink is applied to the cylinder and scraped from the surface using a doctor blade.
The remaining ink is in the crevices, and some of this is transferred to the paper under great pressure. Since the density of the crevices can vary smoothly, there is no need to break a continuous tone image into areas of black and white, as needs to be done for letter-press and the offset lithography which is used for virtually all book and magazine printing today. So the camera would have split the light into three colours and exposed three glass plates simultaneously. From these, three gravure printing plates or cylinders were prepared. Whether this was printed with rotary cylinders or flat plates I do not know.