Who is O. P. Riegel, you ask? He was, in 1921, an executive of the McCall Pattern Company, and he gave an address that was covered by America’s Textile Reporter, which is probably now my new favorite magazine. Here’s part of his address to the Mid-Year meeting of Jobber’s Association of Dress Fabric Buyers (oh that is straight out of an O. Henry story!), held at the Waldorf Astoria; you can read the whole thing here.
This seems to cover the birth of the printed pattern. So cool.