Color depth triangle does enclose a much larger gamut, so whether more than three primaries results in a difference to the human eye is not yet proven, since humans are primarily trichromats, though tetrachromats exist. Color depth Color depth or colour depth (see spelling differences), also known as bit depth, is either the number of bits used to indicate the color of a single pixel, in a bitmapped image or video framebuffer, or the number of bits used for each color component of a single pixel. For consumer video standards, such as High Efficiency Video Coding (H.265), the bit depth specifies the
Forel-Ule scale sea and lake water colors, as they appear to an observer ashore or on board a vessel. The method is used in conjunction with the Secchi disk submersed to half the Secchi depth. The method was developed by François-Alphonse Forel and was three years later extended with greenish brown to cola brown colors by the German limnologist Willi Ule. The Forel Ule scale, a color comparator scale, has been described by Wernand and van der Woerd (M. R. Wernand, H. J. van der Woerd, "Spectral analysis of the Forel-Ule Ocean colour comparator scale.", J. Europ. Opt. Soc. Rap. Public. 10014s