Solid Background Remover
Remove a flat background colour by selecting it, with edge feathering, spill suppression and a flood fill mode that only removes background connected to the edges.
Last reviewed by the Radiatus Cloud team
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Colour matching removes matching pixels everywhere
Selecting a background colour and deleting every pixel like it also deletes anything in the subject that happens to be the same colour: a white shirt against a white backdrop loses the shirt. Flood filling inward from the edges avoids this, because it only removes background that is actually connected to the outside of the frame. A white shirt surrounded by the subject is never reached, so it survives.
Spill is what makes a cutout look pasted on
Light bounces off the backdrop onto the subject, so the edges of a person photographed against a green screen have a green tint several pixels deep. Removing the background leaves that tint behind, and it is immediately visible once the subject is placed on a different background. Suppressing it means detecting the backdrop colour in near-edge pixels and pulling it back towards neutral, which is why professional keying tools have a spill control at all.
Hair and semi-transparency need more than a threshold
A hard cutout gives every pixel either full opacity or none, which works for solid objects and fails on hair, fur, glass and motion blur, where a pixel is genuinely part background and part subject. Handling those properly requires estimating the mixing proportion per pixel, which is what dedicated matting tools do. A threshold with feathering approximates it and will always look approximate on fine detail.
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Frequently Asked Questions
Why does part of my subject disappear?
Because colour matching removes every matching pixel wherever it is, including inside the subject. The flood fill mode only removes background connected to the frame edges, which leaves interior areas of the same colour intact.
What is colour spill?
The backdrop colour bouncing onto the subject, which tints its edges. It remains after the background is removed and becomes obvious against a new background, which is why suppression is a separate control from the removal itself.
Why do the edges of my cutout look harsh?
Because a threshold makes each pixel fully opaque or fully transparent, while anti-aliased edge pixels are genuinely a mix of both. Feathering approximates the blend; it cannot recover the true proportions.
Can this handle hair?
Only approximately. Hair, fur, glass and motion blur produce pixels that are partly background and partly subject, and getting those right needs per-pixel matting rather than a threshold. This will always look approximate on fine detail.
What format should I save as?
PNG or WebP, both of which support transparency. JPEG has no alpha channel and composites the transparency onto a background colour, usually black, without warning.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Upload an image with a flat background and pick the colour to remove.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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