AI tool colors black and white photos automatically

Enlarge / performs AI photo colorization using text prompts to refine.

Benj Edwards / Ars Technica

A Swedish machine learning researcher named Emil Wallner has released a free web tool called that automatically colorizes black and white photos using AI. After uploading a photo, users can choose a color filter or refine colors using a typed text description. uses a deep learning model to classify images, which guides your initial guesses about the colors of objects in a photo or illustration. “I made a custom AI model that uses the image and text to generate colorization,” Wallner wrote in a message to Ars. “One model creates the text and the other takes the image and text to generate the colorization.”

After uploading an image, the site’s elegant interface provides an estimated caption (description) of what it thinks you see in the image. If you don’t like any of the preset color filters, you can click the pencil icon to edit the caption yourself, which guides the colorization model via text message.

To test it out, we took a photo of a small pumpkin and decolorized it in Photoshop. We then uploaded the black and white version and experimented with the selection of the pre-made filters that offers. Once we find a good filter, we edit the legend to refine the colors describing the objects in the scene. For example, originally thought the pumpkin was a “claw” and didn’t recognize the sidewalk. But once we put those terms into the written message, the colors made more sense. We further refine the image later (not shown in the example below) by specifying “green leaves” for the background.

An original Ars test photo (left), one uncolored (middle), and one colorized by (right).
Enlarge / An original Ars test photo (left), one uncolored (middle), and one colorized by (right).

Benj Edwards / Ars Technica

For now, is available as a free service, but Wallner plans to add a paid option. The site processes the images online, in the cloud. Regarding the privacy of uploaded photos, the site says: “We do not store your images.” But as with any cloud service, take it with a grain of salt when it comes to private photos. Refreshingly, does not require any kind of user account registration at this time.

So far, has delighted people at Hacker News who have used the tool to colorize photos of beloved family members, historical photographs, and more. A variation of Wallner’s colorization technology has also been available as robot on Twitter since the end of last year. Have fun coloring.

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