Set of 3 4-page metamerism charts each with 1 glued-in Pantone metamerism sticker.
It is lacquiered with 2 differently pigmented colors that blend seamlessly. For the correct D65 light source with CIE spectrum, both color fields appear almost identical (a minimal difference is apparent due to pigmentation).
If the light source substantially deviates from the D65 standard light in spectrum or color temperature, both fields will reflect the incoming light differently and you will see 2 colors.
Please note that the metamerism chart is not suitable for determining the spectral properties of daylight tubes. This can only be done using a light meter. The sticker enables you only to check whether the daylight conditions are appropriate or you are in a lighting environment that is totally unsuitable for color testing.
Term definition:
Metamerism or metameric colors refer to color pairs that look identical when a defined illuminant is used and appear differently when another illuminant is used.
Example: Illuminant D65 in standardized lighting booths (correct; color fields look almost identical) and TL84 fluorescent tubes on the office ceiling (incorrect; color fields look very different), as shown in the photos.