PSL Scale methodology
A structured reading of one photograph.
The assessment brings several visible facial relationships together instead of relying on a single ratio. It is designed to provide a broad, explainable range while keeping photo quality and interpretation limits in view.
- Four assessment dimensions
- Photo-quality screening
- Broad ranges over false precision
- Clear interpretation limits
Assessment framework
Balance
Vertical proportion
Horizontal spacing
Face shape
Multiple visual relationships → one considered result range
From photo to result
A four-stage assessment, built around consistency.
Each stage has a different job: prepare a suitable image, check whether it can be read fairly, evaluate several relationships, and present a range that reflects the limits of a single photograph.
- 01
Prepare the photograph
Use one clear, front-facing image with even light, a relaxed expression, and the full facial outline visible.
- 02
Check image suitability
The assessment first looks for obvious issues such as head turn, tilt, blur, obstruction, or framing that can weaken the reading.
- 03
Evaluate key relationships
Facial balance, vertical proportion, horizontal spacing, and visible face shape are considered together rather than in isolation.
- 04
Present a broad range
The result is intentionally grouped into a range. It is a reading of this photograph, not a permanent label attached to a person.
Why photo quality comes first
A sophisticated calculation cannot rescue an unsuitable photograph. Distance, angle, lighting, expression, and crop can all alter visible proportions, so a repeatable setup matters more than chasing a particular result.
What is assessed
Four dimensions create a more balanced picture.
Each dimension describes a different aspect of the visible face. None is treated as a complete definition of appearance on its own.
Left-to-right balance
Compares how corresponding areas align around the apparent centre of the face, including the eye, brow, nose, mouth, and jaw regions.
Most sensitive to head turn, uneven expression, and one-sided obstruction.
Vertical proportion
Looks at how the visible upper, middle, and lower areas of the face relate to one another in the image.
Camera height, pitch, hairline visibility, and crop can change the reading.
Horizontal spacing
Reviews spacing across the visible face and eye region to understand how the composition is distributed from side to side.
Perspective and even a small turn can compress the farther side.
Visible face shape
Considers the relationship between visible facial length and width as one part of the overall assessment.
It is a photo proportion, not a diagnosis of face shape or anatomy.
How the result is formed
Several signals are combined, then simplified responsibly.
The public result focuses on the parts that help someone use it well: what is considered, whether the photograph is suitable, and how much confidence to place in the range.
Multi-factor by design
No single proportion decides the result. The assessment looks for agreement across several facial relationships.
Quality before interpretation
When pose or image quality is weak, the right response is to retake the photograph—not to over-explain an unstable number.
Ranges instead of decimals
A broad range avoids suggesting that a single photograph can support fine-grained certainty that it does not have.
Result philosophy
Useful direction without false precision.
The range is designed for orientation and comparison under similar photo conditions. Moving across a boundary can happen because the image changed; it does not prove that the person changed.
Photo standard
The fairest result starts with a repeatable setup.
These conditions reduce avoidable variation and make two photographs more comparable.
Straight-on position
Keep the camera at eye level and face it squarely, without raising, lowering, turning, or tilting the head.
Comfortable distance
Avoid a very close wide-angle selfie. Use a stable position and repeat the same distance for future comparisons.
Even illumination
Soft front light should keep both sides readable without hard shadows, glare, or blown highlights.
Neutral presentation
Relax the brows, mouth, and jaw, and keep hair or accessories away from the facial outline.
Interpretation boundaries
What the result should—and should not—be used for.
The assessment is useful when its scope stays narrow. It summarizes selected relationships in one image and does not replace human judgment or professional evaluation.
It reads a photograph
A different lens, angle, crop, light, or expression can produce a different result for the same person.
It is not the whole appearance
Skin, hair, movement, expression in real life, side profile, and personal preference sit outside this result.
It is not a population ranking
The range is not a percentile, rarity estimate, or comparison with a representative population sample.
It is not medical advice
Do not use the result to diagnose a condition or to make treatment or cosmetic-procedure decisions.
Try it with the right context
Start with one clear, front-facing photograph.
Use the free test for a broad PSL Scale range, then read the result alongside its photo-quality notes and measurement summary.
Free · no sign-up · one clear photograph