TOLERANCE

Methodology

This project is an argument about measurement, so it publishes its own. Every threshold below is the one the code actually uses.

How a variant is made

What we would fix with more budget

Trust thresholds

Cosmetic efficacy is commonly advertised around a 20% improvement. We take 20 points on the engine's raw 1–100 scale as the reference effect of that size. A metric can only support such a claim if its own noise is comfortably smaller, so we compare each metric's observed range to that reference:

We report the observed range rather than a confidence interval: with a handful of captures, a tight interval would be a fiction.

Raw data

The complete dossiers — every variant's raw scores, provenance labels and unit ledgers — are the exact JSON files the site renders: Subject A, Subject B, Subject C. The code that produced them is at github.com/Biniyoyo/tolerance.

The canons

We report conformance to each canon's stated ideal. We do not report a percentile: we have no population distribution, and inventing one would be the exact sin this project exists to expose.

The Neoclassical Thirds

anthropometric

Renaissance art theory, formalised in 19th-century anthropometry

The face divides into three equal horizontal parts: hairline to brow, brow to base of nose, base of nose to chin.

Encoding — Perfect Corp's horizontal_third returns the three sections as percentages. The canon's ideal is [33.3, 33.3, 33.3]; we sum the absolute deviation of each section and map it to conformance over a 30-point tolerance.

This is the canon most often quoted as a beauty standard. It was tested against real faces and found to describe almost nobody.

Measured conformity of real faces:

  • Southern Chinese adults — 0% met the facial three-section canon
  • North American Caucasian adults — met by only a minority; Farkas concluded the canons cannot serve as normative standards

Farkas LG, Hreczko TA, Kolar JC, Munro IR (1985). Vertical and horizontal proportions of the face in young adult North American Caucasians: revision of neoclassical canons. Plast Reconstr Surg 75: 328-338.

Jayaratne YSN, Deutsch CK, McGrath CPJ, Zwahlen RA (2012). Are Neoclassical Canons Valid for Southern Chinese Faces? PLoS ONE 7(12): e52593.

The Rule of Fifths

anthropometric

Classical proportion theory; the orbital canon in modern anthropometry

Face width divides into five equal vertical parts, each one eye-width across.

Encoding — vertical_fifth returns the five sections as percentages. The ideal is [20, 20, 20, 20, 20]; we sum absolute deviations and map over a 40-point tolerance.

Conformity to this canon varies sharply by ancestry. A face that 'fails' it is not deviant; the canon was drawn from a narrow sample.

Measured conformity of real faces:

  • Southern Chinese adults — 0% met the orbital canon
  • Afro-American adults — conformity substantially lower than in the original Caucasian sample

Farkas LG, Hreczko TA, Kolar JC, Munro IR (1985). Vertical and horizontal proportions of the face in young adult North American Caucasians: revision of neoclassical canons. Plast Reconstr Surg 75: 328-338.

Farkas LG, Forrest CR, Litsas L (2000). Revision of neoclassical facial canons in young adult Afro-Americans. Aesthetic Plast Surg 24: 179-184.

Jayaratne YSN, Deutsch CK, McGrath CPJ, Zwahlen RA (2012). Are Neoclassical Canons Valid for Southern Chinese Faces? PLoS ONE 7(12): e52593.

The Golden Ratio

prescriptive

Promoted commercially from the 1990s as a mask of ideal proportion

The ideal face is phi (about 1.618) times as long as it is wide.

Encoding — face_aspect_ratio is returned as [width, height] normalised to width = 1. We compare the height term to 1.618 and map the absolute difference over a 0.6 tolerance.

This one is a marketing artefact wearing a mathematician's clothes. It is included precisely because it is the number most often quoted online.

The phi-mask proposition is a commercial and popular-science claim rather than an anthropometric finding; reviews of facial proportion note it is not supported as a measured property of attractive faces.

Farkas LG, Hreczko TA, Kolar JC, Munro IR (1985). Vertical and horizontal proportions of the face in young adult North American Caucasians: revision of neoclassical canons. Plast Reconstr Surg 75: 328-338.

The Symmetry Scorecard

vernacular

Contemporary online face-rating communities

Left and right features should match; asymmetry is scored as a defect.

Encoding — We compare left and right eye aspect ratios and, when present, left and right eyebrow arch ratios. Deviation is the absolute left-right difference, mapped over a 1.0 tolerance.

This canon has no scientific standing at all. It is here because it is the one being applied to teenagers for free, every day.

No peer-reviewed standard defines this scorecard. It is included as an artefact of online face-rating culture, not as a scientific measure.