Acrylic/oil (and black texta marker) on photographic paper.
I was desperately overworked when the request for this cover came in. I love Terry's horror fiction, and I just couldn't refuse the man.
In an attempt to reduce the time and effort, I had Terry pose for photos, and used a photo-montage as the basis for an oil painting. The result was luminous and very effective.
However, the photogapher at the photolab I used to take my art to for transparencies had trouble with light bouncing off the surface, and couldn't get the right exposure. Evidently he had never heard of a polarising filter or bracketing.
He went over every little reflection with a black marker in an attempt to cover them up. When he finally got a good exposure for the artwork, you could see every single marker dot. He had even dotted over the face and the glow of candle light. It was heartbreaking, and there was no way to clean off the dots.
I had to go back and paint over the entire surface, this time in acrylics, to make sure there was no reflection. So much for saving time and effort.