I’ve gone off on a tangent from bookbinding into making marbled paper, popular in the mid to late 19th century as endpapers in leatherbound books.
Marbled paper is created by floating diluted watercolor paints onto a marbling “size” – water thickened with carragean (a type of seaweed) extract. The consistency of the marbling size is like that of liquid laundry detergent, and is similarly slippery.
After making the size and allowing it to age at least 12 hours to ensure all of the carragean is dissolved I pour it into a shallow pan and drop the marbling colors on the size . If everything goes as planned, rather than sink to the bottom of the the tray, the spread out the way that oil spreads on water – then I can play around with combs and toothpicks to make a fancy design.
When the design looks good, I lay a sheet of paper (I use 100% cotton Meridian drawing paper by Pentalic) that I’ve treated with a solution of water and alum on the image, and the paint gets absorbed by the paper, and voila – a beautiful marbled sheet emerges.
There is some finesse involved in preventing hesitation marks, spots where the paper was laid down too quickly, or dust marks from marring your design – practice makes perfect though.
I’m still experimenting, but I received The Ultimate Marbling Handbook by Diane Maurer, a well known paper marbler from Pennsylvania, for my birthday and I plan to try all the patterns in the book.