With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Ron Cobb is an American writer.
text_B: A subtractive color model explains the mixing of a limited set of dyes , inks , paint pigments or natural colorants to create a wider range of colors , each the result of partially or completely subtracting -LRB- that is , absorbing -RRB- some wavelengths of light and not others .. paint. paint. color. color. light. light. The color that a surface displays depends on which parts of the visible spectrum are not absorbed and therefore remain visible .. color. color. visible spectrum. visible spectrum. Subtractive color systems start with light , presumably white light .. color. color. light. light. Colored inks , paints , or filters between the watchers and the light source or reflective surface subtract wavelengths from the light , giving it color .. color. color. light. light. If the incident light is other than white , our visual mechanisms are able to compensate well , but not perfectly , often giving a flawed impression of the `` true '' color of the surface .. color. color. light. light. Conversely , additive color systems start with darkness .. color. color. additive color. additive color. Light sources of various wavelengths are added in various proportions to produce a range of colors .. Usually , three primary colors are combined to stimulate humans ' trichromatic color vision , sensed by the three types of cone cells in the eye , giving an apparently full range .. color. color. trichromatic. trichromatic. color vision. color vision
not_related.