Tim Hildebrandt (1939-2006) was half of the Brothers Hildebrandt team of twin artists best known for this:
The Hildebrandt brothers' web site is here and their Wikipedia entry here.
I of course remember that famous Star Wars poster, but had lost touch with their work until I stumbled across
this book at a used and remaindered bookstore in my end of town. It originally dates from 1991, thereby leaving out a good deal of Tim Hildebrandt's work which evolved somewhat since publication.
Hildebrandt's style in the 1970s and 80s was both "tight" and detailed. These characteristics appeal to some folks, but not usually to me.
He normally painted using acrylics on gessoed masonite board and very fine brushes except when blocking in large areas. His palette made use of a moderately large selection of colors: four blues, two greens, a purple, three yellows, three reds, an orange, the usual four browns (sienna, umber), white and Payne's gray. A good deal of attention was paid to warm-cool color relationships, light sources and reflected light -- all this virtually formulaic, but understandable for a commercial illustrator trying to hit deadlines.
What struck me most was how different Hildebrandt's style is than those for fantasy art contemporaries such as Frank Frazetta and Jeffry Jones -- let alone current fantasy art that's mostly done using a computer. Below are a few examples of Hildebrandt's work.