How to Blur Sensitive Information in Screenshots

You are about to paste a screenshot into a bug report, a help article or a team chat, and it shows an email address, a customer's name or an API key. The usual reflex is to blur it. Sometimes that is fine. For anything that would cause real harm if it leaked, it is not.

This guide explains the difference between blurring, pixelating and redacting, why the first two can be reversed, how to hide information properly with any image editor, and how InnoShot keeps cosmetic blur and permanent redaction clearly apart.

Blur, pixelate and redact are not the same

All three make something hard to read, but they do it in very different ways.

The rule of thumb: blur and pixelate are for appearance; redaction is for secrets.

Why blur and pixelate are not secure

Blurring and pixelating do not remove information. They transform it in a predictable way, and the original text still shapes every pixel that is left.

That matters because screenshot text is unusually easy to guess. It is rendered in a known font, at a known size, on a plain background. Someone who wants to read it can type candidate text in the same font, apply the same blur or pixelation, and compare the result with your image until the blocks match. Security researchers have reconstructed text from pixelated and blurred screenshots in exactly this kind of way.

Short values with a limited set of characters are the most exposed: a PIN, the digits of an account number, a one-time code. There is a second risk too: some editors keep the blur as a separate layer in their own file format, so the sharp original is still underneath for anyone who opens the file.

So, if leaking a value would cause harm, do not blur it. Cover it with a solid box, or crop it out.

What to hide before you share

Look for more than the obvious field you were thinking of:

• Passwords, API keys, access tokens and session IDs, including the ones in the address bar
• Account, card and bank numbers, and any ID or reference number tied to a person
• Email addresses, phone numbers and home addresses
• Customer names, order numbers and internal ticket links
• Internal hostnames and URLs
• QR codes and barcodes, which encode data that anyone can scan
• Notification previews, autocomplete suggestions and other open tabs that slipped into the frame

The manual way: cover it with a solid shape

You can do this with the screenshot tools already on your computer and any image editor that can draw a filled rectangle.

1. Take the screenshot. On Windows, press Win+Shift+S to open Snipping Tool. On macOS, press Cmd+Shift+4 and drag an area. In Chrome you can also use DevTools: press F12, then Ctrl+Shift+P (Cmd+Shift+P on macOS), type screenshot and choose Capture screenshot.
2. Open the image in an image editor.
3. Draw a filled rectangle over each secret, with opacity at 100%. Make it slightly larger than the text so no tops or tails of letters peek out.
4. Flatten the image and export a new PNG or JPEG. Do not share the editor's own project file, which may keep the original under the shape.
5. Open the exported file, zoom in and check every box.

If a value sits near the edge, cropping it out entirely is even simpler.

Change the page before you capture

There is another approach that never puts the secret into the image at all. In Chrome, right-click the text, choose Inspect, then double-click the text in the Elements panel and type a placeholder such as [email protected]. The change exists only in your browser tab and disappears when you reload, but anything you capture in the meantime shows the placeholder instead of the real value.

Where the manual method goes wrong

• A semi-transparent shape or highlighter stroke leaves the text readable underneath.
• Shapes added on top of an image in a document or slide can be moved or deleted later by whoever receives the file.
• The same value often appears twice, for example in a form field and again in the page title or URL.

The InnoShot way: blur for looks, redact for secrets

InnoShot is a free Chrome extension for capturing and editing screenshots. Its editor has three privacy tools, and they are not equal: Blur and Pixelate are cosmetic, and Redact is permanent. InnoShot is coming to the Chrome Web Store; the download page links to the listing once it is live.

Step by step

1. Capture the page. Press Alt+Shift+V for the visible area, Alt+Shift+S to select an area, or Alt+Shift+F for the full page, or click the InnoShot icon in the toolbar. The capture opens in the editor in a new tab.
2. Choose the redaction tool and drag a box over each secret. Redaction boxes are always fully opaque; their opacity cannot be lowered by accident.
3. For details that only need softening, such as a colleague's avatar or unrelated background content, use Blur or Pixelate instead.
4. Export the image as PNG, JPEG, WebP or PDF. Redactions are flattened into every exported image and PDF, and into the raster part of an SVG export.
5. Open the exported file and check it, as you would with any other tool.

Redacted pixels also stay hidden inside InnoShot itself. If you add a magnifier to enlarge part of the screenshot, it never samples what is under a redaction box; it shows the box. The docs page on blur, pixelate and redact has the details of each tool.

Project files keep the original on purpose

InnoShot can save your work as an editable .innoshot project file, for example as a backup or to hand over to someone who will keep editing. Project files keep the original pixels on purpose, so a redaction in a project is still an editable layer and the original is still inside the file.

When you save a project that contains redactions, InnoShot warns you and offers Apply redactions to source. That burns the boxes into the stored image irreversibly. Do this before you share a project file or a project backup with anyone. For anything else, share an exported image or PDF rather than the project.

Everything stays on your computer

InnoShot runs entirely in your browser. There is no account, nothing is uploaded and it makes no network requests, so the unredacted original never leaves your computer through InnoShot. Captures and projects are stored locally in the browser. If other people use the same Chrome profile, delete the capture from your history when you are done, or apply the redactions to the source.

Common mistakes

Blurring something that is actually a secret. If it is a password, token, key or account number, redact it. If a real key has already been shared in a screenshot, even a blurred one, treat it as exposed and replace it.

Using a spotlight blur as a privacy tool. Spotlight effects can blur or dim everything outside a focus area. That is a presentation effect and just as cosmetic as the Blur tool.

Making the box too small. Leave a margin around the text so the edges of letters do not give it away.

Sharing the project instead of the export. A project file is for editing. Exports are what you send.

Forgetting older copies. Adding a redaction now does not change images you already exported or pasted into a chat. Replace those too.

Wrapping up

Blur and pixelate are useful for keeping a screenshot tidy and for hiding details that are low risk. For anything that must stay private, cover it with an opaque box and export a flattened image, whether you do it by hand in an image editor or with InnoShot's Redact tool. Once your screenshot is safe to share, you may want to point readers at the part that matters; the guide to highlighting one part of a screenshot covers that, and the screenshot editor page shows the full set of tools.