From the Contact form:

I’m researching the industrialization of four-color process printing. Your printing history timeline, as well as many blog posts other sites, states that in the year 1906 “CMYK four-color wet process inks developed by the Eagle Printing Ink Co.” Can you please share the references for this entry? I know Eagle Printing Ink was later part of a merger with other firms to form General Printing Ink (later Sun Chemical). However, I cannot find any resources that verify the claim that Eagle Printing Ink developed the four-color wet process inks. I am interested in tracing the history that led to this development and how the four-color process spread from there. Your help is much appreciated.

Brian Gamm