Tracking hair growth with a photo a day

Hair grows roughly a centimetre a month. That is far too slow to notice in a mirror and exactly fast enough that a year of daily frames turns it into something you can watch happen.

Why daily beats monthly here

The obvious approach is a photograph on the first of each month, and it produces twelve frames that jump. Different light, different angle, different distance — and with only twelve, every difference between photographs reads as loudly as the growth does.

Three hundred frames drown that noise. Any one day's odd lighting is a single frame in a run and disappears at speed. The daily habit is not discipline for its own sake; it is the sampling rate at which the signal finally exceeds the noise.

The eyes are the anchor

Selfeed crops each frame around your face with your eyes at a fixed point. For this particular subject that matters more than usual: what you are trying to see is a length changing relative to your face, so the face has to be the thing that stays still.

No tripod, no mark on the wall, no same-room requirement. Face the camera roughly and the alignment is arithmetic done afterwards.

What is kept, and for how long

Every day's frame stays for good on a free account. The original photograph is kept ninety days free, and for as long as you keep the account on Selfeed Pro. A project whose whole point is the length of time it covers should not have a retention policy you find out about later.

Who sees it

Nobody, unless you choose a handle, turn your public profile on and feature an album — three separate acts, and the featured album is one album rather than the account. Undo any of them and you leave every feed and every home screen at once.

If you do share it, the frames reach people who follow you on their home screen, quietly, with no notification. Growing something out is a long stretch of no visible progress, and somebody watching turns out to be a durable reason to keep taking the photograph through the middle of it.

Start from the photos you have

On iOS, past days can be filled from the camera roll — open a day and Selfeed offers the shots from it with a single clear face. A free account reaches ninety days back, about eleven seconds of film; Pro reaches the whole library. If you started growing it out before you found this page, the series can start where the hair did.