Effect of Color Materials on Aging Behavior of Hanji

Hanji, a traditional Korean paper, has been served as the primary base material for oriental paintings.In recent years, modern colored paints, along with traditional ink, have also been applied in oriental painting, but research on their aging stability remains limited.This study evaluates the aging stability of two types of Hanji commonly used in art, treated with ink, acrylic paint, tube paint, and powdered pigment.For acrylic paint, both diluted and undiluted paints were applied to examine the effect of concentration.Accelerated aging were conducted under humid and dry conditions, and changes in L*, a*, b* values, brightness, tear strength, folding endurance, and water contact angle were measured.The results showed that dry aging caused more significant changes than humid aging.Neither the presence and type of color materials nor acrylic paint concentration significantly affected color changes during aging.Colorant treatment reduced the tear index, but rather improved folding endurance, especially in the relatively lower grade Hanji.Among the paint types, tube paint showed the highest reduction in tear strength and folding endurance, indicating lower aging stability.Acrylic paint exhibited lower contact angles and faster droplet penetration than other color materials, regardless of aging method and Hanji type.Concentrated acrylic paint was advantageous for tear strength but unfavorable for folding endurance, with no changes in contact angle due to aging.Consequently, the aging behaviors of Hanji treated with modern colorant materials was similar to that of ink, showing sufficient potential for use as a color material for oriental painting.