Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color perception, most often the CIE 1931 XYZ color space tristimulus values and related quantities.

The effective temperature of a star is the temperature of a black body with the same luminosity per surface area (F Bol) as the star and is defined according to the Stefan–Boltzmann law F Bol = σT eff 4.Notice that the total luminosity of a star is then L = 4πR 2 σT eff 4, where R is the stellar radius.The definition of the stellar radius is obviously not straightforward.

At right is displayed the web color light pink.The name of the web color is written as "lightpink" (no space) in HTML for computer display. Although this color is called "light pink", as can be ascertained by inspecting its hex code, it is actually a slightly deeper, not a lighter, tint of pink than the color pink itself. A more accurate name for it in terms of traditional color nomenclature ...

The earliest example of a pyrometer thought to be in existence is the Hindley Pyrometer held by the London Science Museum, dating from 1752, produced for the Royal collection.The pyrometer was a well known enough instrument that it was described in some detail by the mathematician Euler in 1760.. The potter Josiah Wedgwood invented a different type of pyrometer to measure …