31. For example, showing how to calculate the color rendering index of standard illuminant FL4 using the procedure outlined in the article. 32. However, when the two objects are seen under different illuminants , the cone absorptions do not correlate with the true values. 33. Whale oil was used as a cheap illuminant , though it gave off a strong odor when burnt and was not very popular. 34. The gas produced during the coking of coal was allowed to escape unused until William Murdoch began to promote coal gas as an illuminant . 35. To perform spectral analysis of a source, monochromatic light at every wavelength would be needed to create a spectrum response of the illuminant . 36. They chose the reference 10 degree observer and Illuminant D65 to characterize the uniform space and a neutral gray background of 30 % reflectance. 37. It is as old as whale oil, which was first used in the 18th century as an illuminant in lamps and to make candles. 38. Priest proposed to use " the scale of temperature as a scale for arranging the chromaticities of the several illuminants in a serial order ". 39. The maximum absolute error for color temperatures ranging from 2856 K ( illuminant A ) to 6504 K ( D65 ) is under 2 K. 40. It is common to use the LMS color space when performing chromatic adaptation ( estimating the appearance of a sample under a different illuminant ).
