# Visible Planck radiance data

Original data: **CIE 2019, Colour-matching functions of CIE 1931 standard
colorimetric observer**, International Commission on Illumination (CIE),
Vienna, AT. DOI: [10.25039/CIE.DS.xvudnb9b](https://doi.org/10.25039/CIE.DS.xvudnb9b).
Source: [official dataset](https://cie.co.at/datatable/cie-1931-colour-matching-functions-2-degree-observer).

The unchanged CSV and accompanying official metadata are provided under
[Creative Commons Attribution–ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/).
That license also applies to the derived Planck-radiance table and manifest in
this directory. Retain this attribution and license link when redistributing
or adapting these data. This data license does not purport to relicense the
separate application code. No endorsement by CIE is implied. No warranties are
given; the original dataset identifies its quality as nominal.

Changes: Vanyx integrated ideal Planck spectra against the original 360–830 nm,
1 nm CIE matching functions, converted XYZ to linear sRGB, clipped negative
out-of-gamut channels and restored original photopic luminance, normalized to
the CIE Y integral of a 6500 K emitter, then sampled/quantized the result into
1024 log-temperature RGBA binary16 texels. RGB is radiance; the fourth channel
is relative CIE Y and is **not opacity**. The source samples are unchanged.

The official CSV SHA-256 is
`fa663e3535a7e0763a745993a1f0a192eb0275ac46ad2d1befd7626841e713c1`;
its published MD5 is `17cca777db64b17170f06f67ce9d3ab7`.
The retained metadata SHA-256 is
`03abcaecf4e63d77045ef57c4514b52c8bb1a46dd18e1f93a50044a0f4f481c8`.
Source URLs, the derived asset hash, numerical checks and model limitations
are recorded in `planck-visible-v1.json`.