This atlas presents colors not only as they appear visually, but as they are spectrally structured.

In addition to standard color specifications (HEX, Lab D50/2°, HLC), two spectral–physical parameters are provided:

• λ*_ext describes the spectral dominance of a color, indicating whether its reflectance is biased toward shorter or longer wavelengths.
• ARBE λ*V2 denotes the energetic balance point between absorption and reflection within the visible spectrum (380–730 nm).

Both parameters are computed directly from measured reflectance spectra and are independent of illuminant, observer model, or color space.

The atlas thus reveals where colors are energetically stable and where, despite a similar visual appearance, spectral differences and metameric risks arise. Use the filters, sorting options, and scatter view to compare colors on a physically grounded basis.

Note: ARBE λ* is not a color space and not a replacement for Lab or ΔE, but an additional layer of physical color description.