Mike Hinge: Digging a Foundation study sketch

This is a an original prelim or study for an advertisement or other commercial commission, that I have just uncovered among odds and ends from an old Hinge portfolio that was filled with advertising references.  It's unsigned, done in watercolors and inks on tracing paper, image 16" x 10" on paper 17" x 11", and has a slight crease across the middle that doesn't interfere with the art.  Happy to also include a letter attesting to authenticity.

Ships from Santa Fe, NM