Red Scale

Red Scale turns a single photo into a simple redness score from 0 to 5.

Take one photo that includes the sample and a white or grey area in the same frame. Drag and release once on the white or grey area, then once on the sample. Red Scale uses the neutral area to account for the lighting, reads the colour, and returns a grade from 0 to 5 — stamped onto the photo so it stays with the image.

Save photos into folders and view them as a timeline to follow how the colour changes over time. Add a short note to any reading.

How it works:
• One photo, with a white or grey area in frame for reference
• Drag and release on the reference, then on the sample
• Get a 0–5 redness grade, stamped onto the photo
• Build a photo timeline and track change over time

Everything stays on your device. Red Scale works fully offline and needs no account.

Lighting and your phone's camera affect the result, so treat each grade as an estimate. For the most consistent readings, take your photos the same way each time.