Why blurring a face isn't enough
Blurring feels safe, but it's one of the most commonly defeated privacy techniques. Here's why a soft blur or pixelation can be undone, and what to use instead.
Blur and pixelation are reversible
A blur doesn't delete information - it spreads it around. The original detail is still mathematically present, just smeared. Researchers have repeatedly shown that blurred and pixelated faces can be reconstructed or re-identified, and modern AI models make this easier every year (see McPherson et al., 2016).
Pixelation has the same flaw: it averages blocks of pixels rather than removing them. With enough samples or a trained model, those averages can be reversed back toward the original face.
What actually works: opaque redaction
The only reliable way to protect a face is to overwrite it. An opaque cover replaces the face with a solid block of a single colour - there is no underlying signal left to recover, no matter how good the attacker's tools are.
BlurBaby defaults to this Redact method for exactly this reason. The Sticker and Pattern options are just as safe: they fill the whole region opaque first, then draw an emoji or a playful pattern on top, so the face is destroyed and the result still looks intentional.
Where blur still has a place
Blur isn't useless - it's fine for aesthetics, like softening a license plate in a fun travel photo where privacy isn't the goal. That's why BlurBaby keeps a Blur option, but clearly marks it as aesthetic-only. If your goal is protecting a child or removing someone identifiable, don't rely on it.
FAQ
Can AI really un-blur a face?
In many cases, yes. Both blur and pixelation preserve enough of the original signal that machine-learning models can approximate or re-identify the face. Treat them as cosmetic, not protective.
Is a black bar enough?
Yes, as long as it's fully opaque and covers the whole face. That's exactly what BlurBaby's Redact does - it replaces the pixels rather than blending them.
Why does BlurBaby still offer Blur?
Because it's genuinely useful for non-sensitive, aesthetic edits. We keep it available but label it clearly so no one mistakes it for real protection.