Upper : lower vermilion height
Height of the upper lip vermilion (red lip) at the midline divided by the lower.
How to read it
the upper vermilion is thin relative to the lower. This is the commonest configuration in every reference group; the widely quoted 1:1.6 "ideal" would place the majority of humans below it by construction.
upper and lower vermilion heights are in the typical proportion for the reference group.
the upper vermilion is comparatively full relative to the lower.
Lip fillers, lip-liner overdrawing and pursing all change this value; it is a poor biological signal in the selfie population.
Reference values by population
| Reference population | Female (mean ± SD) | Male (mean ± SD) | n | Source |
|---|---|---|---|---|
| North American White | 0.842 ± 0.206 | 0.848 ± 0.207 | 2326 | Farkas 1994/2005 (NA White young adults) prov. |
| East Asian | 0.85 ± 0.197 | 0.857 ± 0.188 | 618 | Farkas 2005 (Chinese/Japanese/Vietnamese/Thai pooled); Jayaratne 2012 (Southern Chinese, n=103) prov. |
| South Asian | 0.9 ± 0.202 | 0.905 ± 0.205 | 210 | Farkas 2005 (Indian); Metgudmath 2022 prov. |
| African / African diaspora | 0.88 ± 0.181 | 0.885 ± 0.185 | 300 | Farkas 2005 (African-American, Zulu, Angolan) prov. |
| Middle Eastern | 0.842 ± 0.206 | 0.85 ± 0.205 | 348 | Farkas 2005 (Turkish, Iranian, Egyptian); Al-Sebaei 2015 (Saudi, n=168) prov. |
| Hispanic / Latino | 0.857 ± 0.188 | 0.864 ± 0.192 | 120 | Farkas 2005 (Mexican-American) prov. |
| Not specified — show pooled | 0.864 ± 0.236 | 0.869 ± 0.234 | 3922 | Unweighted pool of the six groups above prov. |
Where these numbers come from
Transcribed from the cited anthropometric literature; SDs of ratios are propagated conservatively (independence assumed). Entries marked prov. await line-by-line audit against the primary tables — see the norm provenance note.
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). For a typical 300 px inter-pupil photo that is ≈12 px per landmark, which is why small ratios and angles get wide intervals. A number without an interval is a number pretending to be more precise than it is.
References
- Kar, Muluk, Bafaqeeh & Cingi (2018). Is it possible to define the ideal lips? Acta Otorhinolaryngol Ital 38(1):67–72. doi.org/10.14639/0392-100X-1511
- Farkas, Katic & Forrest (2005). International Anthropometric Study of Facial Morphology in Various Ethnic Groups/Races. J Craniofac Surg 16(4):615–646. doi.org/10.1097/01.SCS.0000171847.58031.9E
Related: how bone-level measurements are taken from a photo · methodology · all insights