This is an SVG reproduction of Figure 43 from page 205 of Map Projections: A Working Manual by John P. Snyder, published as Professional Paper 1395 by the USGS.[1]  The caption for this map in that document is:
GS-50 projection, with lines of constant scale factore superimposed.  All 50 States, including islands and passages between Alaska, Hawaii, and the conterminous 48 States are shown with scale factors ranging only from 1.02 to 0.98
Snyder, John P. (1987). Professional Paper 1395 United States Geological Survey. p. 205.
John P. Snyder; retraced by Kbh3rd