The description of two of his paintings read: Oil on canvas. So I must assume the one you posted in also oil on canvas.

I’ve seen his work. It’s LARGE. So if you are going to do Diebenkorn, be prepared to shell out for canvas.

I used to be a great admirer. But my old art teacher, Bob Stoller, went through a Diebenkorn phase, and I felt that the influence was detrimental to his own style. So now I have mixed feelings about Mr. D’s work.

there’s not much traffic in this subsection. have you browsed wetcanvas home page and the possibilities here? when you have a question about oils, find the technical forum subsection here in oils. there’s a forum for acrylics as well. should you have questions on using charcoal in/on oils or acrylics, post your questions in oils/acrylics to hear from the most seasoned experts. you might be so kind as to start with googling, let’s say “wetcanvas sealing charcoal on acrylic painting”, see that the dates are this side of 2010 and read those hits first :). i’m a beginner and have never built supports/studied priming, so no advice from me i’m afraid.

i found diebenkorn’s “10 rules when beginning a painting”. have to print them or find a way to have them on the studio wall.

here’s a few words on his technique from conservators:
http://www.conservators-converse.org/2012/06/40th-annual-meeting-psg-session-may-9-relating-artist-technique-and-materials-to-condition-in-richard-diebenkorns-ocean-park-series-by-ana-alba/