(dependent solely on the perceptually achromatic luminance Y, but not the mixed-chromatic components X or Z, of the CIEXYZ colorspace from which the sRGB colorspace itself is derived), and it is plain that this appears similar in perceptual lightness to the original color image. Luma is roughly similar, but differs somewhat at high chroma, where it deviates most from depending solely on the true achromatic luminance (Y, or equivalently L*) and is influenced by the colorimetric chromaticity (x,y, or equivalently, a*,b* of CIELAB). HSL L and HSV V, by contrast, diverge substantially from perceptual lightness. {{multiple image | align = center | image1 = Fire breathing 2 Luc Viatour.jpg | width1 = 220 | alt1 = A full-color image shows a high-contrast and quite dramatic scene of a fire breather with a large orange-yellow flame extending from his lips. He wears dark but colorful orange-red clothing. | caption1 = Fig. 13a. Color photograph (sRGB colorspace). | image2 = Fire-breather CIELAB L*.jpg | width2 = 220 | alt2 = A grayscale image showing the CIELAB lightness component of the photograph appears to be a faithful rendering of the scene: it looks roughly like a black-and-white photograph taken on panchromatic film would look, with clear detail in the flame, which is much brighter than the man's outfit or the background. | caption2 = Fig. 13b. CIELAB L* (further transformed back to sRGB for consistent display). | image3 = Fire-breather 601 Luma Y'.jpg | width3 = 220 | alt3 = A grayscale image showing the luma appears roughly similar to the CIELAB lightness image, but is a bit brighter in areas which were originally very colorful. | caption3 = Fig. 13c. Rec. 601 luma {{nobr|Y'''}}. | footer = }} Though none of the dimensions in these spaces match their perceptual analogs, the value of HSV and the saturation of HSL are particular offenders. In HSV, the blue primary and white are held to have the same value, even though perceptually the blue primary has somewhere around 10% of the luminance of white (the exact fraction depends on the particular RGB primaries in use). In HSL, a mix of 100% red, 100% green, 90% blue—that is, a very light yellow —is held to have the same saturation as the green primary even though the former color has almost no chroma or saturation by the conventional psychometric definitions. Such perversities led Cynthia Brewer, expert in