Duotone
Map shadows and highlights to two colors.
This runs in your browser. Nothing is uploaded.
About Duotone
Maps the dark and light parts of an image onto two colours you pick, producing the two-tone poster treatment in your browser without the file going anywhere.
Duotone earns its keep in brand work. A section header, a slide background, a card image in a deck — anything that has to sit inside a fixed palette without looking like a stock photo dropped into a layout. You choose a Shadow colour and a Highlight colour, and every photograph you feed it comes back in the same treatment.
The tool measures each pixel's brightness on a 0-to-1 scale, then mixes your two colours in that proportion. A black pixel becomes your Shadow colour precisely, a white one becomes your Highlight colour precisely, and everything else lands proportionally between them. The original hue contributes nothing beyond its share of that brightness figure. Alpha survives, so transparent PNGs stay transparent.
Discarding hue is both the point and the risk. Two objects photographed in different colours but similar brightness come out identical, so a red apple against green leaves can disappear into its own background. Choose colours that differ in lightness as well as hue: a dark navy against a pale cream works, while two mid-tone colours produce mud.
How to use Duotone
- 1Drop a photo onto the panel or click to browse.
- 2Choose a Shadow colour for the dark end and a Highlight colour for the light end.
- 3Click Apply preview to see the mapping.
- 4Click Download to save the two-tone image.
What it won't do
- Two colours only — no tritone and no multi-stop gradient map.
- All original hue information is discarded; only brightness survives the mapping.
- Low-contrast source images produce a narrow, muddy result.
Common questions
Which colour goes where?
Shadow replaces the darkest pixels and Highlight replaces the brightest, with a straight blend across everything between. If the result looks inside out, you've swapped the two. The defaults are a near-black for shadows and a blue for highlights, giving a cool dark treatment — reverse them for a light, airy one.
Why does my duotone look muddy?
Almost always because the two colours are too close in brightness, leaving the image in a narrow band with no separation. Test it by imagining both colours converted to grey: if they'd look the same, the duotone will look flat. Running auto-enhance or levels on the photo first so its tones fill the range also helps.
Can I use three colours or a full gradient map?
No — two colours and a linear blend between them is the whole feature. A tritone or a multi-stop gradient map needs more control than this page has. What you can do is duotone the photo, download it, drop it back in and adjust with levels, which moves where the blend sits without changing the endpoints.
Does it work on a logo with a transparent background?
Yes, and transparency passes through, so only visible pixels are recoloured. Bear in mind that a flat single-colour logo has almost no brightness variation, which means nearly every pixel maps to the same point between your two colours. Duotone rewards photographs with a full tonal range, not flat graphics.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation