Is this safe for sensitive documents?

Yes. The image is processed entirely in your browser using a canvas — nothing is ever uploaded to a server, so it is safe for IDs, bank statements and private screenshots.

What is the difference between blur and black box?

Blur softens the region so the layout stays visible, while black box fully covers it with a solid rectangle for stronger redaction.

Can the blur be reversed?

No. The exported PNG bakes the blur or black box into the pixels, so the original detail is permanently removed from the saved file. There is no separate layer to peel back.

How strong is the blur?

The blur uses an adjustable radius from a slider, defaulting to 16 pixels. Larger radii make text and faces completely unreadable, which is recommended for redacting IDs and account numbers.

Can I redact more than one area at once?

Yes. Drag a rectangle for each region you want to hide; every box is applied. You can undo the last box or clear them all and start again.

Is black box better than blur for redaction?

For truly sensitive data, a solid black box is safer because heavy blurring can occasionally be partially reversed by attackers. Black box covers the pixels entirely with no recoverable information.

What format is the output?

The result is exported as a lossless PNG, which preserves sharp edges on the redaction boxes and avoids re-compressing the rest of the image.

Blur & Redact Image — Gera Tools

Blur or redact private details in any image

Need to hide a face, a license plate, an email address or an account number before sharing a screenshot? This tool lets you draw boxes over any image and either blur or black them out. Because it runs entirely in your browser, it is safe for IDs, invoices, bank statements and other private documents.

How it works

The image is drawn onto an HTML <canvas> at its true pixel size. When you drag a rectangle, the tool records its coordinates. For each box it then either:

Black box: fills the rectangle with a solid black fillRect, removing all detail.
Blur: clips to the rectangle, sets ctx.filter = blur(Npx) (radius from the slider, default 16px), and redraws the image so only that region is softened.

All boxes are baked into the pixels, so the saved file has no recoverable original detail.

Example

You upload a screenshot of an invoice and want to hide the customer’s account number. Choose Blur, set the strength to 24px, and drag a rectangle over the number. The digits become an unreadable smear. Add a second box over the email address, then click Export PNG to download the redacted image.

Mode	Method	Best for
Blur	Canvas blur filter (adjustable radius)	Hiding faces while keeping layout
Black box	Solid fill rectangle	Maximum-security redaction of text and numbers

Everything happens on a local <canvas> — the image is never uploaded, so nothing leaves your device.