“There are five parent colors in Japanese art: parent colors Blue (SEI), yellow (AU), black (koku), white (BYAKU), combinations and red (SEKI). These in combination (CHO GO) originate other colors as follows: Blue and yellow produce green (midori); blue and black, dark blue (ai nezumi); blue and white, sky-blue (sora iro); blue and red, purple (murasaki); yellow and black, dark green (unguisu cha); yellow and red, orange (kaba); black and red, brown (tobiiro); black and combinations white, gray (nezumiiro). 

These secondary colors in combination produce other tones and shades required. Powdered gold and silver, and crimson made from the saffron plant are also employed. The colors, excepting yellow, are prepared for use by mixing them with light glue upon a saucer. With yellow, water alone is used. In addition to all the foregoing there are other expensive colors used in careful work and known as mineral earths (iwamono). They are blue (GUNJO), dark or Prussian blue (KONJO), light bluish-green (GUNROKU), green (ROKUSHO), light green (BYAKUGUN), pea green (CHA–ROKU SHO) and light red (SANGO MATSU). 

The use of primary colors in a painting in proximity to secondary ones originated by them is color to be avoided, as both lose by such contrast; and when a color-scheme fails to give satisfaction it will usually be found that this cardinal principle of harmony, called iro no kubari, has been disregarded by the artist. Color in art is the dress, the apparel in which the work is clad. It must be suitably combined, restrained, and attract no undue attention (medatsunai). True color sense is a special gift.”

– Henry P Bowie: The Laws of Japanese Painting c.1911