Blur, Pixelate, or Black Box: Which Redaction Is Safe?
Blur, pixelation, and a black box are often treated as three ways of doing the same job. They are not. Blur and pixelation keep a transformed version of the original pixels. A solid block replaces them. That difference decides whether the hidden detail can be recovered, and it is the reason a light blur is a poor way to hide a password or an account number.
Blur & Pixelate offers the first two effects. The third is usually drawn in an image editor. Knowing what each one leaves behind makes the choice straightforward.
Quick answer
Use a solid opaque block for anything that must stay secret: names, addresses, account numbers, number plates, passwords, and text on a screen. Blur is for softening a background, not for redaction. Pixelation is stronger than a light blur, but small blocks can still leave enough structure to guess or partially recover. Export a flattened copy and strip metadata.
What each method does to the pixels
Blur averages each pixel with its neighbours. The detail is spread across the area rather than deleted, which is why a mild blur can sometimes be reversed or partially recovered. Pixelation averages blocks of pixels and replaces each block with one colour. Small blocks preserve the layout of light and dark; large blocks remove more, but the original is still transformed rather than replaced.
When blur is acceptable
Blur is useful when the aim is to make a detail less prominent, not to make it secret. Softening a busy background behind a product, or reducing the distraction of a crowd, is a reasonable use. A strong blur can also hide a face in a personal photo where the risk is low, provided the blur is heavy and the whole face is covered.
It is a poor choice for text, numbers, and anything that could identify a person or an account. If you use it, choose the strongest setting, cover beyond the edges, and save as PNG. A JPEG can reintroduce blockiness around the blurred area and make text readable again.
When pixelation is the better effect
Pixelation is often used for faces and number plates because it looks deliberate and is stronger than a light blur. The size of the blocks matters. Small blocks can leave enough of a shape for a person or a tool to reconstruct part of the detail. Large blocks remove more, but they can still preserve the outline of a word or a face.
How to use a black box properly
The box must be fully opaque. A semi-transparent box lets some of the detail show through, and a box on a separate layer can be moved or removed if the file is not flattened. Cover the whole detail and a margin around it. Check that the box is part of the exported pixels, not an annotation that the viewer can hide.
Check the export and the metadata
Reopen the exported file at 100% and inspect the edges of every covered area. Look for reflections, duplicate details, and text that appears elsewhere in the frame. A redaction that covers one copy of a name but leaves another is still a disclosure.
Finally, strip metadata and rename the file. A photo can carry location and device details, and a screenshot can carry a filename that identifies a client. Blur & Pixelate runs in your browser, but the output is still a file you may share, so remove private details before it leaves your hands.
For the full photo workflow, read How to Blur a Face, Plate Number, or Address in a Photo. For screenshots specifically, see How to Blur Sensitive Information in a Screenshot.
Common questions
Which is more secure, blur or pixelate?
Neither is safe for short pieces of text. Both average neighbouring pixels, and with enough of the original structure preserved, text can sometimes be reconstructed. A solid black box destroys the information outright, which makes it the safer choice for anything confidential.
When is blur the right choice?
Blur is suitable for faces or backgrounds you want to de-emphasise rather than hide, and for content where partial visibility is acceptable. It reads as gentler than a black box in a public post. It is the wrong choice for a document number or a password.
Does pixelating work better than blurring on text?
Not reliably. Pixelation replaces blocks of pixels with a single averaged value, and the shape of short text can survive that. The larger the blocks, the more is lost, but the safest approach for text remains covering the area completely with a solid block.