Colour Science & Perception
what the eye settles, and what it cannot
Generator

Four pigment templates at 566 nm, each normalised to its own peak

The same peak wavelength through four templates: the Govardovskii nomogram this site uses, the same nomogram with its secondary band removed, Lamb's 1995 nomogram which Govardovskii's is a refinement of, and two Gaussians of the same width — one in wavelength, which is symmetric, and one in wavenumber, which is what an absorption band is usually approximated by and which is asymmetric the wrong way in wavelength. The two published nomograms are almost on top of each other. What separates them from the caricatures is the long tail towards the short wavelengths, and what separates the site's from Lamb's is the secondary band rising to 0.25 of the peak below 400 nm — a feature that sits where the lens has almost stopped transmitting and that no treatment of colour vision this collection has read mentions at all.
Four pigment templates at 566 nm, each normalised to its own peakThe same peak wavelength through four templates: the Govardovskii nomogram this site uses, the same nomogram with its secondary band removed, Lamb's 1995 nomogram which Govardovskii's is a refinement of, and two Gaussians of the same width — one in wavelength, which is symmetric, and one in wavenumber, which is what an absorption band is usually approximated by and which is asymmetric the wrong way in wavelength. The two published nomograms are almost on top of each other. What separates them from the caricatures is the long tail towards the short wavelengths, and what separates the site's from Lamb's is the secondary band rising to 0.25 of the peak below 400 nm — a feature that sits where the lens has almost stopped transmitting and that no treatment of colour vision this collection has read mentions at all.0.000.250.500.751.00400450500550600650700750GovardovskiiGovardovskii, α onlyLamba Gaussian in wavelengtha Gaussian in wavenumberλmax 566 nmwavelength / nmabsorbanceL cone, 566 nma population of eyes · the pigment template, varied

Drawn at its defaults, in the shape an eye is built out of. It takes no options at all, so every essay calling it gets this exact drawing.

Called by 4 essays

the blast radius of changing it

What the eye does

The population rests on a template

Two hundred observers here are built from one formula fitted to microspectrophotometry in 2000. The obvious alternative — the tabulated cone fundamentals — is not available, and the reason is the finding. A tabulated fundamental has no peak wavelength to move, so the moment it is used the population collapses to a single observer.

 What the eye does

A template is mostly its tail

Four pigment templates matched to the same width at the same peak, differing only in which side of the peak their half-maximum reaches further. Ordered by that one number, the observers they build are ordered by how far they sit from the standard one — and the two with the tail on the wrong side cost two and four times what either real nomogram costs.

 What the eye does

The band below four hundred

The pigment template every observer here is built from carries a second, smaller absorption band in the ultraviolet, published at 0.26 of the main one. Dialling it from nothing to twice that moves the median observer monotonically away from the standard one, with no interior optimum — which is what a physical constant looks like when nothing downstream is pulling it anywhere.

 Where the model breaks

Three choices reached

Two rounds ago this collection named three things it rested on and could not audit — a unit, a diagonal and a template. All three are now reached, and the interesting part is not the three answers but that four of the round's own predictions were refused by the arithmetic and one of its measurements was wrong in a way only a cross-check caught.

All 155 generators · what each essay asks for instead