from Fancyclopedia 2 ca. 1959
The hektographed artwork that appeared in Spacewarp around 1947 was distinctive in that hekto-ink painting was used to give rich solid colors after which line drawings were mimeoed in. The system was actually suggested by Vaughn Greene, but Bob Stein was its greatest practitioner.

from Fancyclopedia 2 Supplement ca. 1960:
Oh, was I ever offbase here!! Steinpix and mimeo-hekto were not only two separate artforms, but Stein gafiated before mimeo-hekto was invented. As a matter of fact, Art Rapp explains, it was the disappearance of Bob Stein's superb hekto-pencil artwork that inspired him to devise mimeo-hekto to replace this feature of Spacewarp's cover-art.