“Keys of a spectral light-colour piano”
Recently in the LIMA conference: http://lima-project.fr/programme-de-la-journee-industrielle-lima/ Noël Richard was tlaking about the colour differences across the visual EM spectrum and said that the DeltaE L*a*b* (1976) formulae were suited to compute it. I am not sure I did the right thing in the picture above (it’s still a bit complicated and obscure to me…) but this picture, as it would be printed by my Epson, should contain something close to the rendering of equally-colour-different EM bands. The picture contains 31 bands, like “keys” of a colour piano… The background is a 10% relative luminance neutral grey and each “key” has the same power.
Notice that the bands are very close in the yellow, and even closer in the blue-green areas: that’s where we are supposedly most sensitive to frequency-difference.
Notice that on the other hand the bands are far from each other in the red area.
Original spectral data: 31 gaussians with a variance of 1nm (click on the diagram to zoom)