Well for you Ray... Photo-era magazine, Volume 28 edited by Juan C. Abel, Thomas Harrison Cummings, Wilfred A. French, A. H. Beardsley p. 145. "The New Utocolor Paper" by A. Le Mée. Now you can go to the library! If you're in Japan though, that might be quite a feat in itself.
I'd like to make a crude Utocolor paper. What was unique about it (construction wise), apart from just layering CMY on a piece of paper?