Blur faces

Why blur a face before sharing

A photo from a school trip, a reunion or an accident is often worth publishing, but not with every face in it. A likeness is personal data and sharing it needs consent. With children, doubly so. Blurring the faces is the quickest way to share a photo without dragging anyone else into it.

The same goes for covering a number plate, a document number or an address on an envelope when the photo is heading into a listing or a discussion thread.

The blurred pixels really are overwritten

A blur filter in a phone app, a sticker in a presentation or a black rectangle in a PDF can all be removed, because the original image is still underneath. Here the pixels of the resulting picture are overwritten, so the original face is not in the downloaded file and there is nowhere to get it back from.

A weak blur carries a different trap: the gentler the blur, the better the chance a face can be computed back out of it. When someone really must be unrecognisable, push the strength slider right, use a coarse mosaic, or black the area out altogether.

How to mark the areas

• A tap creates an area of a sensible size, handy for covering a face quickly.
• Dragging draws the area exactly, say a narrow strip over a number plate.
• Tapping inside a finished area removes it again.
• The oval suits faces, the rectangle suits plates, documents and text.

Chrome on Android and some other browsers offer built-in face detection. The Find faces button uses it where it exists and marks them for you. Even then it pays to look over the photo yourself: profiles and partly covered faces often slip past the detector.

Frequently asked questions

Is the photo uploaded to a server?

No. The whole edit runs in your browser and the photo never leaves your computer. You can tell because the tool still works with the internet disconnected.

Does the location data survive in the photo?

The saved picture is drawn onto a canvas, so no EXIF metadata carries across, including the GPS coordinates. The original file still has them, so share the edited one.

What format is the photo saved in?

The one it arrived in: a JPEG comes out as a JPEG, anything else as a PNG. An unnecessary conversion would only cost quality or inflate the size.

Does it handle several faces at once?

Yes, mark as many areas as you like. They are all computed together and the undo button removes the last one.