Color
Duotone Image Filter
Pick an image and two colours to recolour it as a duotone, then download the result.
What this is
A duotone filter replaces every colour in an image with a gradient between two colours you choose. It works in two stages: each pixel's brightness is measured, then that brightness selects a position between your dark colour and your light one. Because the result depends only on brightness, any image immediately adopts your palette — which makes this a fast way to make photos from different sources read as one family.
How it works
Brightness is measured with weights that follow the eye's sensitivity: green contributes most, blue least. Using a plain average of the three channels makes certain colours read too light or too dark, and human faces are the first place it looks wrong.
Choose two colours with a real difference in brightness between them. Two colours of similar darkness produce a shapeless mass, because the available brightness range is too narrow to separate any detail.
How to use it
- Choose an image Photos with clear contrast work best; a flat image stays flat.
- Set the dark and light colours The dark colour replaces the shadows, the light one replaces the highlights.
- Download the result The result saves as a PNG at your source image's resolution.
Common questions
- What is a duotone effect?
- A duotone is an image whose colours are all replaced by a gradient between two colours, selected by each pixel's brightness. The technique comes from two-ink printing and is now used widely to make photos from varied sources read as one identity.
- Why does my duotone look flat and detail-free?
- Most likely because your two colours sit at similar brightness levels, leaving no range to separate shadows from highlights. Pick one clearly dark colour and one clearly light one, and the detail returns.
- Does the tool reduce my image's resolution?
- No — the download uses your image's original resolution. The on-screen preview is scaled down so it stays responsive while you change colours, but the downloaded file is reprocessed at full size.
Notes
- Images are processed in the browser and never uploaded.