How to redact sensitive information from a screenshot
Making text unreadable is not always the same as removing it.
Blur and pixelation transform the original pixels but can retain measurements of them. A solid mask replaces the selected pixels instead. For passwords, seed phrases, addresses, names, account details, private messages, or other sensitive text, use solid replacement rather than cosmetic blur.
1. Identify every sensitive detail
Look for the obvious secret and the information surrounding it:
- names and usernames
- email and physical addresses
- phone numbers
- account and wallet identifiers
- private messages
- QR codes
- profile photographs
- timestamps and location clues
- browser tabs and window titles
- reflections and repeated information
2. Use secure masking
Open BlueMask and leave Secure masking selected. BlueMask accepts a PNG, JPEG, or WebP up to 35 MB (35 × 1024 × 1024 bytes), 24 megapixels, and 12,000 pixels on the longer side. Draw over the complete sensitive detail, including its edges.
Cosmetic blur is appropriate for visual effects. It should not be used as the privacy boundary for sensitive text.
3. Cover enough context
A tightly fitted box may reveal the length of a name or number. Sometimes covering the complete line or surrounding label reveals less information.
Avoid publishing several differently masked versions of the same image. Comparing them may expose details that one version hides.
4. Review at 100%
Inspect the complete image at full size. Check edges, repeated details, reflections, thumbnails, and information elsewhere in the screenshot.
5. Export a new flattened image
BlueMask exports a new opaque PNG named bluemask.png. Transparent areas are flattened onto white. The export keeps the edited image's width and height. It does not copy the original filename, camera details, GPS metadata, or color profile.
Inspect the exported PNG before sharing it.
6. Use the offline edition for highly sensitive images
Download the self-contained edition, disconnect the device before opening the private image, complete the masking and export, inspect the result, and close BlueMask before reconnecting.