Types of Fibers
Kozo, or Mulberry, is used in 90% of washi. It is known for its very long fibers, giving the paper strength and durability. There are two types of Japanese Kozo: Nasu (Ibaraki Prefecture) and Tosa (Shikoku and Kochi Prefectures). It is also grown in China, Southeast Asia incl. the Philippines, Laos, Vietnam, and Thailand. Kozo is essentially a weed, and when it is harvested, will grow back the next year. It is a sturdy plant and grows basically everywhere. Kozo grown in Southeast Asia has a darker color than Japanese, and is thinner and oilier, and therefore is most often bleached. The difference likely comes from water quality, whether or not the water is being filtered through rocks as in Japan; the pH level of the soil; environmental humidity; and the distance between the cultivated plants. Japanese kozo exhibits thicker strands and a lighter color, generally requiring no bleaching.
Gampi
Gampi fiber is rare and fickle. It is almost impossible to cultivate, and needs to be harvested by gleaners. The two most important factors for its happiness are soil and light: it should be not too much light, but not too much shade, and the soil should be a mix of soft and rocky. It takes 7 years for Gampi to reach its first harvest, and after that it can be harvested every 3 years. Gampi looks like young Sakura (cherry tree) when you harvest it, so you have to be very careful to cut down the correct plant! Its original purpose was to hold gold leaf.
Mitsumata
Mitsumata will grow about anywhere. It is easy to identify by the 3-configuration of its branches.
Mitsu = Three. The tradition of using mitsumata as the raw material for Japanese banknotes began in 1879, and they still contain the fibers today, providing durability and strength. Mitsumata tree has beautiful blossoms in yellow, orange and purple and is thus often also cultivated as an ornamental tree.
Uses
Washi is a wildly flexible material to work with and can be applied to many creative pursuits including: Printmaking - Bookbinding - Lighting - Conservation - Sculpture - Drawing - Painting - Mark-Making - Collage - Encaustic - Interior Design - Architecture - Graphic Design - Scrapbooking - Sumi-e - Origami.