One of the crafts I enjoy is paper marbling. The piece on my front door is mine. For centuries, the details about how to marble paper and how to make specific paints were closely-guarded secrets. Often the masters would not reveal all the information even to their journeymen; and, of course, apprentices were completely in the dark. Marbled paper had its major use as endpapers in books. Much paper is put to this use today, especially by the boutique hand-binderies.
This is just a start for this section, so do come back. I'll get some graphics of some of my stuff scanned and up here, too. Yeah, yeah, all I need is a month to devote to this home page to get it whipped into shape!
Below are some links to sites for how-to, history, supplies, and marbling projects for children, usually with water as the medium instead of a "gel" size, although I also have files using shaving cream and liquid starch as the medium.
This is just a start on this page, so please come back.
http://clc.kcsos.k12.ca.us/lesson/~gonzalez/marble.htm has some history of marbling.
http://www.kid-at-art.com/htdoc/lesson39.html has good how-to information (on carageenan size), including some good how-to pictures and a good list of tools and supplies.
http://collections.ic.gc.ca/roedde/family/26.htm has a brief discussion of the art, and http://collections.ic.gc.ca/roedde/family/marble.htm has how-to information, using water as the medium.
http://members.tripod.com/~LuJS/Marbling.html is another how-to, a little more detailed than the previous site. This is a discussion of how to marble with Deka medium.
http://www.pitara.com/activities/craft/82.htm is another how-to done with water.
http://www.createxcolors.com/product_lines/marble_colors.htm more how-to; this one done on size. Also sells products.
http://www.stampin.com/tips/marble.htm gives instructions for marbling done with oil-based "model paint" on water. The graphic is not a good example of paper marbling at all! See the big air bubble?
http://www.hewit.com/acatalog/p-bkmarb.htm has pictures of four of the traditional patterns. How these are made depends on how you comb the paint before putting the paper down.