Holbein Artist Watercolor is a European style transparent watercolor which preserves the brush handling qualities inherent in Japanese watercolor techniques.
More finely ground than any other artist watercolor, Holbein Artist Watercolor is produced without ox-gall, animal by-products or other dispersing agents. This affords the user greater control in the dispersal of their pigments, enhances handling qualities and delivers color of unequaled intensity, purity and reliability for brilliant transparent washes and/or powerful, clean darks.
 
More product detail, please check Holbein offical website :
http://www.holbeinartistmaterials.com/Watercolors