The course materials were LaTeXed/TeXed (so, all black and white).
Now, I wrote my M.Sc. and Ph.D. theses with LaTex and know how powerful it is and how far ahead of its time it was. But for me, LaTex isn't a good choice for course materials. Color is generally a superior way to highlight important points and is definitely better for diagrams. Actually, I livened up my thesis by including colored graphs. I just left big blank spaces on my LaTexed pages and then ran them through the color printer to add the graphs. I also glued color photos into the thesis.
Point of pedantry: it's perfectly possible to use colour in LaTeXed documents. I do it all the time, and many textbooks are developed in LaTeX and use colour.
(I am not saying there aren't reasons to prefer things other than LaTeX under some circumstances. But wanting to use colour isn't one of them.)
