I'm pretty sure this was the first illustration I ever did using Graphix Duo-Shade board, the paper on which Kevin and I would later draw most of the early TMNT comics. The tones -- especially the light ones -- on this particular drawing have faded somewhat, as they sadly tend to do on Duo-Shade originals. I think it has something to do with the nature of the chemicals which combine to make the tones.
I think this was probably done in the late 1970's, and quite possibly for "Hampshire Life". -- PL