Annotate

Blur or pixelate private info in a Mac screenshot

Drag a box over an email, an API key or a face, then pick how it disappears: Pixelate, Blur (secure), Blur (smooth) or Black Out. Plumshot draws the result into the exported pixels, so there's no layer for anyone to drag aside.

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3-day full-feature trialmacOS 14 Sonoma or laterUniversal (Apple Silicon & Intel)

One tool, four obscure types. Switch any box between them from the toolbar.
How it works

How to blur a screenshot on a Mac with Plumshot

It all happens in Plumshot's annotation editor, on your Mac.

  1. Open the screenshot in the editor

    After a capture, click Annotate on the Quick Access thumbnail, or turn on Open annotation window after capture in Settings ▸ Screenshots. Earlier captures open from History.

  2. P

    Pick the Pixelate tool

    Press P, or click the checkerboard icon in the toolbar. Next time, the editor opens with the tool you used last.

  3. Drag over what should disappear

    Draw a box over the email, key or face, and choose the obscure type and Radius in the toolbar. Select a box later to move it, resize it or switch its type.

  4. ⌘↩︎

    Export one flat image

    After a capture, Done puts the redacted copy back in Quick Access, ready to copy, save or drag. Save As (⇧⌘S) writes a PNG or JPEG instead.

Four obscure types

Pick how it disappears

The Pixelate tool draws the box; the Obscure type menu next to it decides what happens inside. Every type stays within the rectangle you drew, and the export uses the same placement as the editor, so a box can't land a few pixels off.

  • Pixelate, the default, averages the area into square blocks. Radius sets the block size, from 4 to 56 (12 to start).
  • Blur (secure) pixelates first, then softens the blocks: it hides detail like Pixelate, with a smoother look.
  • Blur (smooth) is a plain Gaussian blur, good for faces and backgrounds you just want out of focus.
  • Black Out is a solid black box. Nothing of what was underneath survives, so it's the one for secrets.
Before you share

Blur hides detail. Black Out hides everything.

Pixelation and blur throw detail away, but short text such as a password can sometimes be guessed back: public tools have rebuilt pixelated passwords when the font was known. If a leak would hurt, use Black Out, or cut the area off with the Crop panel.

While you edit, every box is its own layer that you can move, retype or undo with ⌘Z. On export, Plumshot draws the screenshot and every visible mark into one new full-resolution image: no layers, no editable boxes, nothing in the file to peel back.

  • Keep every redaction visible in Layers. A hidden layer is left out of the export.
  • Don't hide text with the Highlighter. It's see-through by design.
  • Redaction runs on your Mac. Plumshot uploads nothing and needs no account.
Built-in vs. Plumshot

Can't macOS blur a screenshot on its own?

Not quite. The Markup tools in the screenshot thumbnail and in Preview have shapes with a fill color, but no blur or pixelate, so the built-in way is a solid rectangle drawn over the text. Preview's redaction tool works on selected text in PDFs, not on screenshots.

macOS Markup (screenshot thumbnail, Preview)

  • Free and already on your Mac
  • Cover things with a shape and a solid fill color
  • No blur or pixelate tool for images
  • In Preview, marks on an image file can't be changed after you save it

Plumshot

  • Pixelate, two blurs and Black Out in one menu
  • Boxes stay editable until you export: resize, retype, hide or undo
  • Opens straight from Quick Access after a capture
  • Scriptable too: plumshot annotate takes a blur shape, see the agent guide

The details

Tool
Pixelate, key P in the annotation editor
Obscure types
Pixelate (default), Blur (secure), Blur (smooth), Black Out
Radius
4 to 56 in 11 steps, 12 by default; Black Out has none
Export
One flattened image: Done (⌘↩︎) to Quick Access, or Save As (⇧⌘S)
File format
PNG by default, JPEG in Settings ▸ Storage
Privacy
Processed on your Mac, nothing uploaded
Permission
None to redact; capturing needs Screen & System Audio Recording (Screen Recording on macOS 14)
Command line
plumshot annotate, shape type blur, styles pixelate secureBlur smoothBlur blackOut

Questions, answered

Can I blur a screenshot on a Mac without installing anything?

Not with a real blur. Neither the Markup tools in the screenshot thumbnail nor Preview have a blur or pixelate tool, so the built-in way is a rectangle with a solid fill drawn over the text. Plumshot's editor adds Pixelate, two kinds of blur and Black Out.

Which option should I use for passwords and API keys?

Black Out. Pixelate and both blurs remove detail, but short pixelated text has been reconstructed by public tools when the font was known. A black box leaves nothing to reconstruct.

Can someone remove the blur after I share the screenshot?

There's nothing to remove. Plumshot exports one flat image with the redaction drawn into its pixels, and no layers or editable boxes travel with it. What can't be ruled out is someone guessing pixelated or blurred text, which is why Black Out exists.

Does Plumshot find sensitive information automatically?

No. You decide what to cover by drawing the boxes yourself, and your screenshot never leaves your Mac.

Can I redact an image that wasn't captured with Plumshot?

Yes. Plumshot's own captures open from Quick Access or History, and for any other PNG or JPEG the plumshot annotate command applies the same four obscure types from a JSON spec. See the agent guide.

How much does Plumshot cost?

A one-time $9.90 license, no subscription. Every feature, redaction included, is free to try for 3 days, starting with your first capture. It needs macOS 14 Sonoma or later. Details are on the pricing card.

Anything else? Write to support and a human replies. support@plumshot.app

More of what Plumshot does

Share the screenshot, not the secrets.

Every obscure type is in the 3-day trial, which starts with your first capture. Keep Plumshot for $9.90, once.

Download free trialSee pricing

3-day full-feature trialmacOS 14 Sonoma or laterUniversal (Apple Silicon & Intel)

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