Emma H. Mellencamp is an American art historian. Her essay "A Tale of Black Beauties" originally appeared in Newf Tide, the official publication of the Newfoundland Club of American, in early 1978 (Vol. 9, no. 1).
Mellencamp's essay traces the development of black coat color in Newfoundlands; she correctly notes that most of the earliest depictions of Newfoundlands are of dogs with much more white than is now considered acceptable in black Newfs.
There are other works discssed here at The Cultured Newf of relevance to this issue of coat color in Newfoundlands, and how preferences for color have changed since the breed's early development. Be sure to check out this article in the New York Times from 1966 that discusses the popularity of the Landseer coloration, especially as it related to Landseers and dog shows.
A much more recent discussion of the prevalence of and preference for coat color in Newfoundlands is Dr. J. Bondeson's 2015 article "Historical Analysis of Newfoundland Dog Fur Colour Genetics" available here at The Cultured Newf. (It's a PDF document, so will open in a new tab/window for easier reading.)
The Cultured Newf has also collected a large number of advertisements, most of them from The Times (London), that seeks to help document the prevalence of and preference for coat color in Newfoundlands, beginning in 1760. (Think of it as a sort of raw data :) That section of The Cultured Newf may be found here; the list of ads will open on the left side of this browser window.