Instant designer look
Duotone is a staple of album covers, event posters and editorial art; mapping luminance between two colours gives any photo that polished, intentional graphic style.
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Duotone Image Effect
Map every tone onto two bold colours for a striking graphic poster look.
- Upload
- Single file · 25 MB max
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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Processed entirely on your device
Your file is read, transformed and re-encoded inside this browser tab using JavaScript. There is no upload endpoint — nothing leaves your machine, nothing is stored, and the result is created as a local object URL that disappears when you close the page.
Overview
About the Duotone Image Effect
Create a duotone effect that maps shadows and highlights onto two colours for a bold, screen-printed graphic. Rendered on your device — nothing uploaded.
What duotone does
Duotone reduces an image to its luminance, then paints that brightness ramp between two chosen colours instead of black and white. Dark pixels take the shadow colour, bright pixels take the highlight colour, and everything in between blends smoothly across the two. The result keeps all the shape and depth of the original but wears a bold, unified palette.
Why designers love it
A two-colour treatment instantly makes a photo look designed rather than snapped. It is the signature of music posters, magazine covers and event branding, and it lets a single flat colour scheme tie together images that were shot in very different lighting.
Choosing strong source images
Duotone depends on tonal range, so portraits and subjects with dramatic light and shadow produce the most graphic results. Since only two colours remain, busy multi-colour scenes simplify into clean shapes — often an advantage.
Private, on-device rendering
The colour mapping runs per pixel on an in-browser canvas and is exported as a lossless PNG, so your artwork stays local and the gradient stays perfectly smooth.
Step by step
How to use the Duotone Image Effect
Drop a portrait or high-contrast image onto the upload area.
The two-colour duotone renders instantly across the tonal range.
Subjects with strong light and shadow read best.
Download the duotone PNG for posters, covers and social graphics.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Unifies mismatched photos
Because every pixel is reduced to the same two-colour ramp, a set of inconsistent shots suddenly looks cohesive — great for collages and galleries.
Local and lossless
The colour mapping runs on an in-browser canvas and exports PNG, so the effect is immediate and your file never leaves your device.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
What is duotone versus grayscale?
Grayscale maps tones from black to white. Duotone maps tones between any two colours — here a deep indigo shadow and a warm gold highlight — so the image keeps depth but wears a bold two-colour palette.
Which images work best?
Portraits and subjects with clear separation between light and shadow, because the two-colour ramp needs a full tonal range to show shape. Flat, evenly lit photos lose definition.
Is this the same as a gradient map?
Yes — duotone is a two-stop gradient map applied to luminance, which is exactly how designers produce the effect in professional tools.