Uneven skin tone
Tone uniformity across regions
How much the lightness of the skin differs from one region of the face to another, as a standard deviation.
Also searched as blotchy skin, uneven complexion and patchy skin tone.
How to read it
the regions of the face sit close together in lightness: an even tone in this photograph.
a moderate spread of lightness between the regions of the face.
the regions of the face differ widely in lightness: a patchier tone in this photograph.
Uneven lighting is indistinguishable from uneven tone in a single photo.
Why every value has an error bar
Every value Canthion reports carries a 1σ uncertainty propagated from MediaPipe Face Mesh's published accuracy (3.96% of inter-ocular distance mean absolute error per landmark, Kartynnik 2019). On a typical photo with 300 px between the pupils, that is about 12 px of wander on every point. Small ratios and angles inherit it, so their intervals are wide. A number without an interval is a number pretending to be more precise than it is.
Common questions
What is uneven skin tone?
How much the lightness of the skin differs from one region of the face to another, as a standard deviation. Lower = more even tone.
How is uneven skin tone measured from a photo?
From the pixels of the photograph, not from landmarks: the region (all regions) is converted to CIE L*a*b* and the value is read as a statistic of those pixels. Because it depends on lighting, it is reported relative to the rest of the same photograph and marked lighting-dependent.
How reliable is uneven skin tone from a photograph?
Skin values depend on the light the photograph was taken in, so they are reported relative to the rest of the same photograph and never as an absolute. Uneven lighting is indistinguishable from uneven tone in a single photo.
Related measurements
The rest of the skin set, then the nearest measurements elsewhere on the face. Every one is computed on the same photograph, in the same run, with its own error bar.
Also: how bone-level measurements are taken from a photo · methodology · glossary · all 35 insight pages