Lip Shape Analyzer

Cosmetics needed the words first. Makeup artists wanted an explanation for why one liner technique gave different results on two mouths, and today's categories are the residue of that practical work.

Because the traits describe different relationships, they layer. A mouth can be full and wide and carry a pronounced bow at once, so the tool reports a dominant trait plus any secondary ones. Forcing a single label onto a mouth throws away most of what's useful.

The vocabulary stays loose for a second reason. This is the least stable feature on a face: hydration, temperature, time of day and recent talking all shift the visible tissue measurably. That variability caps how precise any reading here can be.

Landmarks form a dense closed contour around both lips, and every reported value comes from that outline.

• Vermilion height is the vertical thickness of each lip at the midline.
• Upper-to-lower ratio divides the height of the top lip by the height of the one beneath it.
• Mouth width ratio divides commissure-to-commissure span by the distance between the pupils.
• Fullness ratio divides combined vermilion height by that same commissure span.
• Commissure tilt measures the angle of the corner-to-corner line against the lower lip midpoint.
• Cupid's bow definition measures the vertical drop between the twin peaks and the philtral notch.

Most mouths carry more volume below than above, which is why the reference is not 1:1. Those six values map onto the traits compared next.

Full and thin describe volume alone. Wide and round describe proportion alone. Heart-shaped and bow-shaped both need a defined cupid's bow, but heart-shaped also needs extra volume underneath, which produces the taper behind the heart outline. Downturned is a corner-position trait and attaches to any of the others. Heavy upper turns up less often than heavy lower. Each points toward a different liner strategy.

Liner strategy follows the measurement rather than the label: hold a prominent shape in place, or build apparent volume where there is little.

• Full mouths stay controlled under a matte or satin finish, since gloss pushes them forward.
• Thin mouths gain depth from liner set just outside the natural border plus a light central highlight below.
• Wide mouths shorten when color stops short of the corners and density builds centrally.
• Heart-shaped mouths want the bow traced precisely rather than filled over.
• Round mouths lengthen when liner extends a fraction toward each commissure.
• Downturned mouths lift when liner sits a fraction above the natural corner.
• Bow-shaped mouths suit a defined edge; blur it only for a softer effect.
• Heavy upper and heavy lower mouths even out under a deeper tone on the thinner side.

Undertone matters as much as outline. Cool skin suits blue-based reds and berries, warm skin suits coral and brick, neutral skin carries both. All of it assumes the photograph caught your mouth at rest.

Relax completely. That's the hardest instruction here and the one that matters most, because pressing the lips together even slightly cuts visible vermilion height by around a fifth. Let them rest closed but unpressed, teeth lightly apart.

Shoot straight on at eye level. A downward angle shortens the lower face and compresses the mouth in projection. Keep the light frontal and even: light from above throws a shadow beneath the mouth that the contour detector reads as extra height, and a hard ring-light highlight washes the border out.

Photograph bare skin if possible. Lipstick and liner exist to move the apparent border, so a made-up mouth gets measured as the shape the makeup drew. Avoid shooting straight after eating, after a hot drink, or after cold wind, since each changes volume temporarily.

Accuracy is highest for the proportional values. Width against interpupillary distance, the upper-to-lower comparison and corner tilt all compare landmarks inside a single image, so scale and camera distance cancel out. Absolute millimeter figures are not offered, because one photograph carries no reference for real-world size.

Fullness is the least stable output. Vermilion height varies through the day with hydration, and it changes across years as collagen density declines and the border softens. A morning reading can differ from an evening one, and that difference is a real change in tissue rather than a fault.

The traits are cosmetic conventions, not clinical categories. They describe the mouth you have on the day you photograph it, and they exist to help you pick products and technique. No output here evaluates health or implies any shape needs correcting.

Eight traits, six numbers, one browser tab. The vocabulary came out of makeup practice rather than anatomy, the landmarks trace a closed contour around both lips, and the table sets each defining measurement beside its visual signature. Liner strategy follows the measurement, capture depends on a relaxed unpressed mouth under even frontal light, and the proportional values hold up far better than the fullness reading. Nothing here is clinical. Open the lip shape analyzer, take a bare-lipped photo at eye level, and read the ratios beside the label.