Blur Image

Introduction

Sometimes you need to hide part of an image without deleting the file. Support engineers blur account numbers in screenshots before posting to public forums. Journalists obscure faces in protest photos when subjects did not consent to identification. HR redacts salary figures on scanned forms. Parents blur other children's faces in school event photos shared online. Blur is irreversible — which is exactly what you want for privacy — but uploading sensitive screenshots to a cloud blur service creates a new leak vector.

Certoflow's Blur Image tool applies adjustable Gaussian blur locally in your browser. Set a radius from 1 to 50 pixels, preview the result, and download PNG output. The entire image blurs uniformly — for selective redaction, combine with Crop Image to isolate regions or use a desktop editor with brush masks. Processing stays on your device with light and dark theme support for reviewing redacted captures at any hour.

What this tool does

The blur workflow supports privacy and design softening:

1. Upload — load one or more JPEG, PNG, or WebP images.
2. Set blur radius — choose strength from 1px (mild) to 50px (heavy).
3. Process — blur the active file or batch-process all loaded images.
4. Download — save PNG with blurred pixels baked into the export.

Blur applies to the full frame uniformly through a CSS blur() filter on the canvas pipeline. There is no rectangular selection or brush tool — the tool optimizes for whole-image softening and quick full-frame redaction when the entire capture is sensitive.

No server upload. No recovery of original detail from the exported file.

How it works

Certoflow draws the source image to canvas and applies filter: blur(Npx) before export, where N is your chosen radius. The filter convolves neighboring pixels, reducing high-frequency detail proportionally to the radius value.

Larger radii destroy more information. A radius of 8px mildly obscures small text in a screenshot; 20px and above makes faces unrecognizable at typical viewing sizes. There is no perfect radius for all cases — preview at 100% zoom on the sensitive region.

Export uses PNG via canvas.toBlob(). Blur is destructive: keep your original file archived separately before processing.

Batch mode blurs multiple images with the same radius setting. Adjust radius and reprocess if the first pass is too weak or too strong.

All computation is client-side. Certoflow does not receive image bytes or blur parameters over the network.

Blur radius guide

Radius	Typical effect
1–4px	Subtle softness, background bokeh mockups
8–12px	Obscure small text, mild face redaction at thumbnail size
16–24px	Strong text redaction in screenshots
30–50px	Heavy privacy blur on faces and identifiers

Start at 8px for mild redaction and increase until sensitive content is unreadable at the display size you expect.

Real-world examples

Support forum screenshot hygiene

An engineer captures a billing error with customer email visible in the header. Blur at 16px locally, verify text is unreadable, attach to GitHub issue. Original unblurred file stays on the secure machine.

Background softness for presentation slides

A speaker blurs a busy office background behind a product demo screenshot so audience focus stays on the UI foreground. Export blurred PNG and place behind a sharp foreground crop in the slide deck.

Parental privacy on group photos

A parent blurs faces of children who are not theirs before sharing a classroom photo in a private group chat. Uniform blur is crude for single faces — crop tightly first when only one region needs redaction.

Document redaction before public records request

A clerk blurs signature lines on a template scan before publishing a sample form. Pair with Strip Image Metadata so EXIF does not leak capture device information alongside blurred content.

Thumbnail anonymization

A researcher publishes dataset preview images with heavy blur so structure is visible but identifying details are not. Batch blur twenty samples with identical radius for consistent presentation.

Common mistakes

Assuming blur is reversible. Exported blur cannot be undone. Always retain the original file in secure storage.

Using too little radius on high-resolution screenshots. Small blur on 4K captures may leave text readable when viewers zoom. Increase radius or downscale with Image Resizer before blurring.

Expecting selective region blur. This tool blurs the entire image. Crop sensitive regions first or use an editor with brush redaction for partial frames.

Blurring instead of stripping metadata. Blur hides visual content but EXIF GPS may remain. Run Strip Image Metadata before external publish.

Saving only the blurred JPEG through multiple lossy passes. Export PNG from this tool; compress once for delivery if JPEG is required.

Trusting blur for classified document safety. Determined adversaries apply deconvolution to mild blurs. Use solid black redaction boxes for high-sensitivity material.

Processing the only copy. Blur destroys detail permanently in the export. Never overwrite your sole master file.

Related tools

Remove location and camera tags with Strip Image Metadata after blurring. Crop Image isolates regions before blur when only part of the frame is sensitive. Image Compressor reduces PNG size for ticket attachments. Grayscale Image desaturates before blur for print-style soft backgrounds. Invert Image is unrelated to privacy but useful for creative edits on already-blurred art.

FAQ

Are my images uploaded to a server?

No. Blur uses Canvas filters entirely in your browser.

Is blur reversible?

No. Blur destroys fine detail in the export. Keep your original file.

What blur radius should I use?

Start at 8px for mild redaction. Increase for stronger privacy on faces or text.

Does blur apply to the whole image?

Yes. The entire frame receives uniform blur. Crop first for partial redaction workflows.

What is the output format?

PNG. Follow with Image Compressor if you need JPEG for upload limits.

Can I batch blur multiple files?

Yes. Load multiple images and process all with the same radius.

Can I use this offline?

Yes, after the page loads.

Does blur remove EXIF metadata?

Canvas export typically strips embedded metadata — desirable for privacy workflows.

Is this sufficient for legal document redaction?

Mild blur may not meet legal redaction standards. Consult policy and use approved tools for regulated material.

Does Certoflow support light and dark theme?

Yes. Controls and previews adapt to light and dark interface themes.