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
- Relight — AI Photo Lighting applied to the real file. A real operator on a real photograph; the skin did not change.
- Capture frames — one image-to-video call returns 81 frames. These are generated, so this axis measures variance across plausible captures of one image, not across genuinely re-shot photographs. Worse, the generator lets expression drift between frames — a raised brow, a changed mouth — so some of the movement we attribute to capture is really the face doing something different. That makes this axis an upper bound on capture noise, not a clean estimate of it. We say so because it is the weaker of the two axes and hiding it would make the whole project dishonest.
- Identical normalisation — every variant is cropped and scaled by the same fixed transform before measurement. Without this, part of the reported variance would be our own preprocessing rather than the capture.
What we would fix with more budget
- Sample frames closer together, or reject frames whose facial landmarks moved, so the capture axis stops absorbing expression drift.
- Re-shoot genuinely separate photographs of a consenting subject, which is the only way to measure real capture variance rather than a generated proxy for it.
- More than four variants per subject. With four readings the observed range is a coarse instrument, which is exactly why we report the range instead of a confidence interval.
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:
- range < 5 points → trustworthy
- range < 10 points → borderline
- otherwise → noise
- all readings pinned to the top or bottom of the scale → saturated
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
anthropometricRenaissance 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.
The Rule of Fifths
anthropometricClassical 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.
The Golden Ratio
prescriptivePromoted 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
vernacularContemporary 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.