Discussion Irt Silk Paper

In a different thread on SCF there was a recommendation for someone to pickup a copy of, Toppan and Holland (1899) A Historical Reference List of the Revenue Stamps of the United States.

So, I did just that. Now I'm dangerous! =)

Letters on page 9 &10 describe silk paper manufactured by the Hudson paper Co. containing silk fiber. The inventory of paper containing silk fiber:
999 sheets 17 x 14 in. Red Fiber,
1003 sheets 17 x 14 in. Red & Blue Fiber

Any other reference to silk paper does not identify colors of fiber contained in the paper.

Are there any other references to the color of the silk fibers?

Somewhere along the line I came to believe that silk paper was only identified by finding blue fibers in the weave. But it appears now that both blue and red identify silk paper... at least paper manufactured by the Hudson Paper Co. And of course, having the silk paper identified by professional certification.