Every ratio, angle and skin read is taken from the pixels you upload. Lens distortion, hard light, a turned head or a filter all become measurement error before any calculation starts. This guide shows how to remove them.
The short version
At selfie distance your nose is much closer to the lens than your cheekbones and ears. Closer things render larger, so the nose and mid-face swell, the face looks narrower, and the ears slip out of view behind the cheeks. This is perspective distortion. It depends only on distance, not on which phone you use. In a controlled study, selfies taken at 30 cm made the nose base look about 30% wider than photos taken at 1.5 m (Ward et al., JAMA Facial Plastic Surgery, 2018).
For the analyzer this is not cosmetic. Nose width, face width, the facial width-to-height ratio, jaw width and ear protrusion all shift. The ratios are internally consistent, so nothing looks wrong, but they describe a face that has been distorted.
Nose enlarged relative to the cheekbones
The analyzer maps 478 facial landmarks, separates hair, skin and background, and reads skin and eye detail from pixels. Each requirement below protects a specific set of results.
Hold the camera at eye height and face it squarely, with your chin neither raised nor tucked. The analyzer rejects photos turned more than 22° or tilted more than 28°, but every degree well below that still costs accuracy: a turn narrows one half of the face and shifts the symmetry, jaw and cheekbone widths, and a tilt changes every vertical ratio and how much of the nostrils shows.
ProtectsSymmetry, widths, facial thirds, canthal tilt
Lips closed and relaxed, not pressed together. Teeth lightly apart, brows at rest, no smile. A strong expression is rejected outright. A mild smile passes the gate but lifts the mouth corners, and the lip-seal read is then withheld rather than guessed.
ProtectsJaw, chin, lips, lip seal
Look into the lens itself, not at the screen, with your eyes open the way they normally rest. Sclera show, lower-lid exposure and the lid-position readings are measured against your iris. A sideways glance or a squint changes all of them.
ProtectsSclera show, LEE, eyelid position, eye colour
Push hair off your forehead and behind your ears, and remove glasses, hats, headphones and large earrings. The hairline is found by segmenting hair from skin. A fringe or hat hides it and face length falls back to an estimate. Hair over the brows blocks the brow reads, and covered ears cannot be read at all.
ProtectsFace length, upper third, eyebrows, ear protrusion
Face a window or a large soft light so both sides of your face are lit evenly. Overhead light pools in the eye sockets and under the nose, and reads as under-eye darkening. Side light splits the face into a lit and a shadowed half, so shadowed skin is dropped from the texture read and widths become harder to detect. Avoid direct flash: it flattens shape and leaves glare on skin.
ProtectsSkin texture, periorbital darkening, contours
Turn off beauty, portrait and smoothing modes, filters and colour grading. Skin smoothing erases texture, and portrait-mode blur cuts into hair and ear edges. Colour reads are measured relative to your own skin, which absorbs a mild cast, but a heavy warm or cool grade still shifts sclera and lip colour.
ProtectsSkin texture, sclera colour, lip colour
Skip concealer, foundation and eyeliner if you want the skin and eye reads to describe your skin rather than your makeup. Stand in front of a plain wall that contrasts with your hair, so the segmenter can separate hair, skin and background cleanly.
ProtectsUnder-eye, brows, lashes, hairline
Upload the photo straight from the camera, not a screenshot or a copy sent through a messaging app: both compress away the detail the skin reads use. Make sure yours is the only face in the frame. The analyzer refuses photos with more than one face rather than guessing which one is you. Landmarks are reliable once your face is about 140 px tall, but a face 800 px or taller in the original photo gives the texture, brow and eye reads real detail to work with.
ProtectsEvery measurement
Profile angles such as the nasolabial angle, chin projection and jaw angle are measured along your silhouette. A few degrees of rotation moves the nose tip and chin relative to each other and changes all of them.
The analyzer refuses a photo rather than measure it badly. Each message names the problem it found. After a photo is accepted, you can still drag any landmark into place before the results are calculated. Check the hairline, eye corners and jaw points in particular.
Your photos are processed on your device and never uploaded or stored.
