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| Keywords: Blackbody sRGB quantal-units.png CIE XYZ 1931 tristimulus version modified by Judd 1951 and Vos 1978 http //cvrl ioo ucl ac uk/index htm weighted by reciprocal wavelength for quantal scaling with λ<sub>0</sub> 500 nm is arbitrary chosen as reference to keep the ratio near 1 for the spectra in each temperature step <math>X \int_0 \infty I \lambda \ \overline x \lambda \ \frac \lambda_0 \lambda \ d\lambda</math> <math>Y \int_0 \infty I \lambda \ \overline y \lambda \ \frac \lambda_0 \lambda \ d\lambda</math> <math>Z \int_0 \infty I \lambda \ \overline z \lambda \ \frac \lambda_0 \lambda \ d\lambda</math> 3 convert into sRGB using the corresponding matrices this requires some rescaling to avoid oversaturation of any color channel <math> \begin bmatrix R_\mathrm linear \\G_\mathrm linear \\B_\mathrm linear \end bmatrix \begin bmatrix 3 2406 -1 5372 -0 4986\\ -0 9689 1 8758 0 0415\\ 0 0557 -0 2040 1 0570 \end bmatrix \begin bmatrix X \\ Y \\ Z \end bmatrix </math> The sRGB gamma correction is the done for all C R G B as follows <math>C_\mathrm srgb \begin cases 12 92C_\mathrm linear C_\mathrm linear \le 0 0031308\\ 1+a C_\mathrm linear 1/2 4 -a C_\mathrm linear > 0 0031308 \end cases </math> where <math>a 0 055</math> To get quantal weighting the XYZ color-matching functions are divided by the wavelength relative to 500 nm to keep the order of magnitude near 1 Finally 3 convert into sRGB using the corresponding matrices this requires some rescaling to avoid oversaturation of any color channel The result is written into an RGB palette file which can than be visualized by gnuplot In contrast to File Blackbody sRGB energy-units png the white point is near 5300 K implying a slightly bluish-white hue of the Sun 5800 K which contradicts everyday experience own SiriusB 2011-09-03 File Blackbody sRGB energy-units png Cc-zero Color temperature SRGB | ||||
