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How to remove a censor from a picture

Usually not: a solid black box can't be removed, because the pixels under it were replaced. Blur and pixelation are weaker: researchers and free tools have read text back from them, and software has recognised faces through them. If the censor is your own edit on your own phone, you can often revert it.

Blur imageUpdated 3 min read

Solid boxes: nothing to recover

When a picture is saved with a black box over part of it, the file holds black pixels there. No app can work out what was underneath, because that information isn't in the file any more.

There's one exception: a box that isn't part of the picture. A shape laid over a photo in PowerPoint, Google Slides or a PDF editor can be moved away by anyone who can edit the file. That's why you should flatten the image before you share it.

Pixelated and blurred text: sometimes readable

Pixelation averages each block of pixels into one colour, and blur averages each pixel with its neighbours. Both keep a trace of what was there, and text is easy to guess because it's made of a small set of letters.

  • A 2016 study recovered both short and long passages of pixelated and blurred text with hidden Markov models. Its authors concluded that mosaicing and blurring aren't viable ways to redact text.
  • Depix, a public proof of concept, recovers plain text from pixelated screenshots.

Recovery works best on large, plain text in a known font with small blocks or a light blur. It doesn't always work, but you can't count on it failing.

Faces: recognisable more often than you'd think

A 2016 paper showed that neural networks could identify faces protected by pixelation and by YouTube-style blurring, even when people couldn't. That doesn't give back a sharp photo. It means a blurred face isn't always an anonymous one.

AI "unblur" and enhancer apps

Enhancer apps make a picture look sharper by predicting detail that fits. On a blurry holiday photo that can look convincing. On a censored area the added detail is invented, so it shows what the app thinks could be there, not what was. Don't treat it as evidence of what was hidden.

Undoing your own edits

If you censored a photo on your own phone, the original may still be there:

  • iPhone: in Photos, open the picture, tap the Edit button, tap Revert, then Revert to Original.
  • Android: Google Photos lets you undo a redaction with Revert on your device if you saved over the original. Google says people you share the redacted photo with can't undo it.

Censor your own pictures safely

The tool below starts on Solid box with Areas I pick, the setting that can't be reversed:

  1. Choose the photo or screenshot.
  2. Drag a box over each name, number, face or address.
  3. Download it as PNG and share that copy, not the original.

Blur image

Open the full tool

The download is redrawn from the pixels on screen, so the original file's hidden details, such as GPS location, aren't copied into it. For a softer look on faces, pixelate or blur with a high strength, knowing it's weaker than a box. More on the trade-offs on the censor image and pixelate image pages.

Sources

Questions

Can you remove a censor in a picture?

Not a solid box: the pixels under it are replaced, so there's nothing to recover. Blurred or pixelated text and faces can sometimes be read back, which researchers have shown.

How do I remove a censor on iPhone?

Only your own edits, on your own phone. In Photos, open the picture, tap the Edit button, tap Revert, then Revert to Original. That doesn't work on a picture someone else censored and sent to you.

How do you unblur censored text?

Researchers have recovered blurred and pixelated text with statistical models, and Depix is a public proof of concept for pixelated screenshots. It depends on the font, size and settings, and it doesn't work on solid boxes.

Can AI unblur a censored image?

AI enhancers make a picture look sharper by predicting detail, so the result is a guess, not the original. Neural networks have identified faces through blur and pixelation, but nothing can bring back pixels a solid box replaced.