Before computers were used to color animated characters for cartoons, character drawings were transferred to clear plastic sheets (called cels), and the painting was done on the back. This Raisin Bran advertisement took things to another level---the characters had meticulous shading painted right on to the cel. This must have been an astonishing amount of work (possibly airbrushed?). A TV commercial had a much bigger budget and care given to it than the TV shows the ads ran with at the time.
I believe the Kellogg's commercials were produced by Murakami-Wolf-Swenson, which ironically went on to produce the hand-drawn California Raisins Saturday Morning cartoon in 1989, as well as Teenage Mutant Ninja Turtles (among countless other projects).
Ray Raisin was voiced by the legendary Paul Winchell (the original voice of Tigger from Disney's Winnie the Pooh). I believe Sunny was voiced by Joel Cory (who voiced the Helping Hand in commercials for Hamburger Helper).
Two bigger scoops of raisins are the reason Kellogg's Raisin Bran's so pleasin'! That song is stuck in my head now.