Quote Originally Posted by Stephen Benskin View Post
Ron, that graph is from Jones' paper The Evaluation of Negative Film Speeds in Terms of Print Quality, Journal of the Franklin Institute, April 1939, page 502 and 503. The test is best known as the first excellent print test. Psychophysical testing is the definite way to determine print quality. A simplified version of this would be the so called ring-around test which is a popular class assignment at photographic schools. Michael started a thread recently on the fractional gradient method where the first excellent print test was part of the discussion.
Stephen, this type of panel test was used for years by Kodak for evaluating prints. My graph was derived from Mees, Revised Edition, page 878, written specifically by J. L. Tupper, in a chapter contributed by L. A. Jones. These works were all contributions from members of the KRL staff. IDK what Jones did at the time you cite, but he was part of the "Mees Team" at the time Mees wrote his book.

Some excellent treatment of this subject, with examples, is shown in Practical Sensitometry by Wakefield. Example curves and prints are shown from a number of different combinations. Ctein has some very nice examples using modern materials in his book "Post Exposure". I suggest that the contributors to this thread put some of these books on their reading list.