Make picture desaturate with pure CSS

In the BWS developing process, I had to make the images desaturate and then fade them to color at hover. It is possible to make without javascript, only have to use filter and CSS transitions.

How it is possible? First, we have to style the image for it’s final place, and then the magic happens: we can use a desaturate filter for the images, and for hover, we can make it to fade in with CSS transitions.

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