Map a photo onto two colours of your choice, dark to light. Thirteen presets, a swap button, and a strength slider to let some of the original colour back in.
Reduces the photo to brightness, then paints that brightness with a gradient that runs from your shadow colour to your highlight colour. A pixel at 0 percent brightness becomes exactly the shadow colour, one at 100 percent exactly the highlight colour, and a mid-grey lands halfway between them. That is why the effect works on any picture: composition and light survive, colour is replaced. Transparency is kept, so a cut-out on a transparent PNG stays cut out.
A 1920 × 1080 concert photo with a busy, orange-lit crowd. The Navy and amber preset (shadows #1e3a8a, highlights #f59e0b) turns the stage lights amber and everything in shadow a deep blue, and the picture reads cleanly at thumbnail size on a playlist cover. Swapping the two makes the crowd glow and the lights go dark, a completely different mood from the same file. At 65 percent strength the singer’s face keeps a natural warmth under the tint. Exported as WebP at quality 85 the file is about 180 KB.
Duotone is a branding tool: it makes a set of unrelated photos look like one campaign and it lets a brand colour dominate an image without covering it. It is the look of playlist covers, event posters and hero banners with text on top; run Add Text after this for the headline. It is a poor choice when the viewer needs to identify colours, as in product listings, maps or medical images. For a single-colour wash rather than a two-colour map use Colorize Image, and for the traditional brown version use Sepia Effect.
Shadows and Highlights take any colour; the presets are safe pairings with plenty of contrast, and the last one, black and white, is a plain monochrome conversion. Swap exchanges the two, which is often the better version. Strength blends the duotone with the original photo; 100 is the pure effect. In Output, choose PNG to keep transparency or JPEG for the smallest file; the JPEG background colour only matters if the source had transparent areas.
Which colour goes where? Shadows is the colour of the darkest pixels and Highlights the colour of the brightest; every brightness in between is a straight mix of the two. If the result looks inverted, press Swap.
Why does the photo look muddy? Two colours that are close in brightness, for example mid-blue and mid-red, leave no room for contrast. Pick a dark shadow colour and a light highlight colour; the presets are built that way.
Can I keep a little of the original colour? Yes. Lower Strength to around 60 to 70 percent and the original hues show through the tint, which works well for album covers and hero images where you still want skin to read as skin.
Is the image uploaded to a server? No. The two-colour mapping runs in your browser on the pixel data, and nothing leaves your device.
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