set log x set linear y set nokey set nocolkey set size 11 ratio 0.2 set noytics set xlabel 'Temperature' set noylabel f(lambda) = phy.Bv(phy.c/lambda,c1) / (c1**4 / unit(6000*K)**4) set colmap colors.spectrum(f,3e3) set sample grid 200x2 set c1range norenorm set title 'Colors of blackbodies of different temperatures' plot [unit(2000*K):unit(20000*K)] x with colormap