Glenn FleishmanOn September 5, 1946, the St. Louis Post-Dispatch switched the printing of its color comics from relief letterpress to rotogravure. Rotogravure was mostly limited to fancy sections, including fashion, color photography, and advertising. The paper seems to be the only one in United States that ever chose to use the very expensive rotogravure process for comics. In these panels, you can see and compare relief versus rotogravure.
Gordon J Holtslander@glennf Copper plate photogravure is also used, not quite as accessible as polymer. https://www.routledge.com/Copper-Plate-Photogravure-Demystifying-the-Process/Morrish-MacCallum/p/book/9780240805276
Copper Plate Photogravure: Demystifying the Process
Copper Plate Photogravure describes in comprehensive detail the technique of traditional copper plate photogravure as would be practiced by visual artists using normally available facilities and materials. Attention is paid to step-by-step guidance through the many stages of the process. A detailed manual of technique, Copper Plate Photogravure also offers the history of the medium and reference to past alternative methods of practice.Copper Plate Photogravure: Demystifying the Process is part o