In this article we are studying the general problem of coloring a periodical plane mosaic, carried out by the action of a crystallographic group. In the first epigraph, we discover the color stains for a plane tiling by means of the conceptualization of plane chromatic composition. The symmetries of a chromatic composition are studied and, in Theorem 1, the plane periodical chromatic compositions are characterized. The second epigraph is dedicated to establishing a method of obtaining the chromatic plane compositions without being necessary that all the colors intervene in equal proportion. The main theorem of the article is the Theorem 2 which by means of the color equation characterizes the successions of subgroups of a crystallographic group which may be the isotropy color groups of a chromatic plane periodic composition. The article is illustrated with multiple examples, extracted fundamentally from the Alhambra of Granada (Spain).