Change photo background colour

Removing the background is only half the job

Most background removers hand you a transparent PNG and stop. That is the wrong output for a document photo, because no government portal accepts transparency — they want a solid colour, and which colour is a rule rather than a preference. Indonesia ties the background of a pas foto to birth-year parity for KTP-e, KIA and kartu kuning. SSCASN wants red. SKCK wants red. The Philippines and several Gulf states want blue. India, the UK, the Schengen area and the United States want white or a very light grey.

Why hair goes wrong against red, and what is done about it

This is the part that separates a real tool from a one-line script. At the edge of a person — through hair, around a shoulder, along a collar — a pixel is not entirely subject or entirely background. It is a mixture, and the mixture already contains the old background colour. Paste that pixel straight onto a new background and the old colour is still in it, which is why cut-outs against a saturated red end up with a grey-green halo around the head.

So before compositing, the old background colour is estimated from the pixels that are definitely background, and then removed from every partly-transparent edge pixel by solving the mixture back to the subject's own colour. The result is that a strand of hair against red is a strand of hair against red, rather than a strand of hair with a ghost of your kitchen wall around it.

Which colour Indonesia actually wants

Published guidance disagrees with itself on this, and it disagrees in both directions depending on which office wrote the page — some say an odd birth year takes red and an even year takes blue, others say the reverse. Rather than pick one and be confidently wrong for half of you, both are offered and neither is chosen for you. Check the instruction on the form in front of you, which is the only source that governs your application.

File size, because that is usually the next problem

SSCASN wants the finished photo under 200 KB. There is a maximum-size field here so you do not have to run the result through a second tool, and it works the same way as the rest of the site: it searches for the highest quality that fits rather than applying a fixed setting.

What this does not do

It changes the background. It does not change your expression, straighten your head, remove glasses glare or make a photograph taken in poor light into a good one. If the original is dim or blurred, the cut-out will be dim or blurred against a clean colour. Take the photograph in daylight, against any plain-ish surface, facing the camera squarely — the background is the easy part to fix afterwards.