Duotone Image Maker

A duotone maps the brightness of a photograph onto a gradient between two colours. The darkest pixels take the first colour, the brightest take the second, and everything in between is a blend. It was originally a printing technique for adding depth to a black and white image with a second ink, and it survives today because the result is graphic, bold and instantly readable at small sizes.

Drop your photo onto the tool, pick a shadow colour and a highlight colour, and the preview updates immediately. Adjust the contrast slider to control how much of the image sits at each end, and use blend if you want the original colours partly visible. Press Apply and save. Nothing is uploaded.

A duotone runs a straight gradient from shadow to highlight. A tritone inserts a third colour in the middle, so the ramp bends through it. That extra control is what lets you build palettes that a two-colour gradient simply cannot reach — a sunset that goes deep red, then pink, then yellow, for example, rather than a flat interpolation between red and yellow that passes through muddy orange.

In tritone mode it decides where the middle colour sits on the brightness ramp. Push it low and the mid colour takes over the shadows, leaving a long stretch to the highlight. Push it high and most of the image sits between shadow and mid, with the highlight confined to the brightest areas. It is the control that decides which of your three colours dominates.

Because the mapping depends entirely on luminance. A flat, low-contrast photo has most of its pixels bunched in the middle of the range, so a duotone of it uses only the middle of your gradient and both of your chosen colours barely appear. Raising contrast before mapping spreads the pixels across the full range so your shadow and highlight colours actually show up. This is why a duotone of a hazy photo looks disappointing until you push contrast.

It mixes between the original image and the full duotone. At 100 percent the result is a pure two or three colour mapping. Lower it and the original colours bleed back through, which gives a graded, tinted look rather than a graphic one. Around 60 to 75 percent is a useful middle ground for photography that should still read as a photograph.

It uses the Rec. 709 luminance formula, which weights green at about 0.72, red at 0.21 and blue at 0.07 because that matches how sensitive human vision is to each. A simple average of the three channels would make blues far too bright and reds too dark, and the resulting duotone would misplace things relative to how you perceive the original.

No. The mapping is built as a 256-entry lookup table and applied pixel by pixel in your own browser. Nothing leaves your device, and the tool keeps working if your connection drops once the page has loaded.

Because the expensive part is done only once. Instead of computing the colour mapping for every pixel, the tool precomputes the result for all 256 possible brightness values and then each pixel is a simple table lookup. That is a fixed 256 calculations regardless of whether your image is one megapixel or fifty.

Yes. Every colour is a standard picker, so you can paste exact hex values from a brand guide. That is the main reason this exists rather than a fixed set of filters — a duotone in your actual brand palette is genuinely useful for headers, social cards and event artwork.

Yes. Add as many as you like and the same palette is applied to every one, which is exactly what you want when building a consistent set of covers, cards or team headshots. Download them individually or take the whole batch as a single ZIP.

Anything your browser can decode: JPG, PNG, WebP, GIF (first frame), BMP, and AVIF or HEIC where supported. You can keep the original format or export as PNG, JPG or WebP.

Yes for PNG and WebP output. The alpha channel passes through untouched, so only visible pixels are mapped. JPG has no alpha, so transparent areas are filled with the background colour you choose first.

No. Duotone is a lossy transformation in the information sense: three colour channels are collapsed into a single brightness value before being remapped, so the original hue data is gone. Keep your source file. Setting blend to zero returns the original in the preview, but once you have saved a duotone the colour information is not recoverable from it.

Images with clear separation between subject and background, strong shapes, and a decent tonal range. Portraits against a plain wall, architecture, and anything with a defined silhouette work well. Busy scenes with lots of similar mid-tones tend to collapse into an indistinct mass, because once colour is removed there is nothing left to separate the elements.

No need. The tool reads luminance directly, so a greyscale conversion beforehand changes nothing and just adds a step. If you want to control how specific colours translate to brightness before mapping, that is a different job — adjust the image first, then duotone it.

Yes. Re-encoding from the canvas drops camera model, GPS coordinates, timestamps and other metadata. If you want to strip metadata without changing the picture, use the remove EXIF tool instead.

No to both. No sign-up, no email wall, no daily limit and no watermark. The output is your image with the palette applied and nothing else added.