Image Redaction

Image redaction permanently removes sensitive information from an image before it is shared. Typical targets are names, email addresses, account numbers, API keys, addresses, faces and private messages.

Proper redaction replaces the sensitive pixels with an opaque fill, such as a solid black box, and exports a new flattened image. After that, the original content is not in the file and cannot be recovered from it.

Obscuring is weaker than removing. Light blur and pixelation keep part of the original signal, and published research has reconstructed pixelated text in some cases. In PDFs, a black shape drawn over text can leave the text itself selectable underneath.

Redaction vs blurring vs cropping

Method	Content removed	Risk
Solid fill, flattened	Yes, inside the box	Low
Blur or pixelation	Partly	Short text and numbers can be guessed
Cropping	Yes, outside the crop	Context may be lost
Shape on a separate layer	No	Layer can be moved or deleted

Where image redaction is used

• Bug reports and support tickets with customer data on screen.
• Tutorials and documentation recorded on real accounts.
• Legal, HR and compliance records.
• Social posts that show an inbox, dashboard or chat.

How to redact properly

1. Work on a copy and keep the original private.
2. Cover each sensitive area with an opaque fill, with a margin around it.
3. Export a new flat image, not a project file with layers.
4. Check the exported file at 100 percent zoom.
5. For PDFs, use a redaction feature that removes text, then search for the redacted words.

Common mistakes with image redaction

• Using a semi-transparent highlight that still shows the text.
• Blurring short numbers, which can be guessed from shape.
• Sharing the original files by mistake. A Temposhot ZIP of frames with annotations warns that it contains the original unedited files.
• Forgetting other places the data appears, such as a browser tab title or a notification.
• Leaving metadata such as location in the file.

Have an image to fix right now?

Cover sensitive areas with solid boxes in the browser with Image Redaction Tool. Files stay on your device.

Common questions

Is the Blur tool enough for passwords and keys?

For secrets, use a solid fill. Blur suits faces and background details where exact recovery is not a risk.

Does redaction remove text from a searchable PDF?

Not when it only draws over the page image, because the text layer can still contain the words. Search the exported PDF for each redacted word to confirm it is gone.

Sources

• Sanitization (classified information) (Wikipedia)

Related resources

• Annotations and framing: editor tools, including Blur.
• Image metadata: data stored outside the pixels.