On-device skin analysis from one photo

Redness rises when the cheek patches carry more a* than a neutral reading. A flush, lingering post-blemish color, and a warm lamp all do that, so the number is how red the surface looks now. Tone evenness falls when one cheek's lightness disagrees with the other, which happens with patchy pigment and also with a window on only one side. Shine is highlight on the cheek, the quick stand-in for a slick surface. Texture contrast rises with roughness, dryness, and a harsh sensor.

The app's advantage is the second scan. Hydration, texture, tone, acne, pores, and redness are stored with the routine you were following, so a change has a before. This page cannot show that line. It can give you today's point.

Clinic systems hold the face still, standardize the lamps, and often shoot more than one pass: ordinary light, a cross-polarized pass that cuts shine so redness and pigment separate, and sometimes ultraviolet that shows what has not surfaced yet. They may also place you next to other people of a similar age. A phone in a bedroom has none of those controls, so it sees less and repeats less exactly.

What the phone has is repetition. It costs nothing and you can run it every week in the same window. The clinic answers a deeper question a few times a year. The app answers whether the routine is moving the six scores between those visits. Neither one diagnoses. A new, growing, bleeding, or non-healing mark needs a dermatologist regardless of either report.

Face a window in the day, with the sun not on your skin. Overhead bathroom lights dig shadows that score as unevenness. Evening bulbs push red and yellow. Flash paints highlights that score as shine. Hold the phone at eye level, about an arm's length away, and look straight into the lens with a relaxed face.

Clear hair off the forehead and cheeks. Skip makeup, skip a just-applied moisturizer, and turn off beauty mode and any smoothing filter. Then repeat those choices next time. A single score mixes your skin with your lighting. Only a repeated setup lets a change in the number mean a change in the skin.

Sleep, a cycle, a cold walk, exercise, alcohol, and a new detergent all show on the surface within a day. Two readings a week apart mostly show that noise. Four to six weeks of photos in the same window, once or twice a week, is where a direction shows up: redness easing after you stopped a harsh acid, texture settling on a retinoid, shine unchanged despite a new cleanser.

This page is the free snapshot. Guided framing and a history live in the app, which is why the QR code under the tool opens the App Store on an iPhone and Google Play on an Android phone.

It cannot see oil under the surface, water in the barrier, or a count of individual blemishes. It cannot separate a flush from inflammation. Those are the jobs of a saved app scan over weeks, and of a clinician when something hurts or is changing.

Rosacea, eczema, a plain flush, and a fungal-pattern breakout can all look red in a photo, and they are not the same decision. A dark spot can be a freckle, a mark left after a blemish, or something that needs a dermatologist, and no color average separates those. If a spot is new, changing, bleeding, or not healing, book the visit and do not wait for a better score.