Background Colour Changer

How to use the background colour changer

1. Choose an image — the background colour is guessed from its border.
2. Adjust the tolerance until the right area is affected.
3. Soften the edge, then download the PNG.

About this tool

Picks a colour and either removes it or swaps it for another. The border of the image is sampled when you open a file to guess the background, since the background is what surrounds a subject rather than what sits in the middle of it.

Be clear about what this is, because the phrase "background removal" now implies something quite different. This matches colours. It does not understand what a subject is, and it has no model of foreground and background. On a flat studio backdrop or a screenshot it works cleanly. On a photograph taken in an ordinary room it will not, because a real background contains hundreds of shades and usually shares some of them with the subject.

Tolerance is the control that matters and it is a genuine trade-off rather than a setting to maximise. Raising it catches more of a varied background and starts eating into anything sharing that colour — a white shirt against a white wall cannot be separated by colour alone, no matter what tolerance you choose.

Colour distance is measured with a perceptual weighting rather than a plain RGB difference, so one tolerance value behaves consistently across hues. A flat RGB distance treats a shift in blue as mattering as much as the same shift in green, which does not match how the eye works and makes the slider feel unpredictable.

Softening the edge fades alpha across a narrow band instead of cutting at the threshold. Without it, the result has the hard jagged outline of something cut out with scissors.

Output is PNG, because JPEG has no alpha channel and would fill transparency with black.

Common uses

• Making a logo's white background transparent.
• Recolouring a flat background in a screenshot.
• Preparing a product photo shot against a plain backdrop.

Frequently asked questions

Will this remove the background from a photo of a person?

Not reliably. It matches colours rather than recognising a subject, so it works on a flat backdrop and fails in an ordinary room where the background has hundreds of shades.

What tolerance should I use?

As low as gets the job done. Raising it catches more background and starts removing anything that shares the colour — a white shirt against a white wall cannot be separated by colour alone.

Why is the output always a PNG?

Because JPEG has no alpha channel. Saving transparency as JPEG fills it with black.