BYTETOOLS

Red Eye Remover

Remove flash red-eye from a photo. Drag a box over the eyes and only strongly red, saturated pixels are corrected — the catchlight survives.

Drop a flash photo with red eyesProcessed locally in your browser — never uploaded

What is the Red Eye Remover?

Red eye happens when a flash fires close to the lens and lights up the blood vessels at the back of the retina.

  • Detects red-eye pixels by the ratio of red to the brighter of green and blue, plus a saturation floor
  • Corrects only inside the oval you drag, so red clothing and lips elsewhere are safe
  • Feathered edge so the fix blends into the face instead of leaving a visible patch
  • Leaves the white catchlight intact, keeping the eye looking alive
  • Numeric selection fields and a whole-photo mode alongside dragging
  • Preview updates live, and the full-size download applies exactly the same settings

How to use the Red Eye Remover

  1. 1

    Drop in the flash photo with red eyes.

  2. 2

    Drag a box around the eyes — the dashed oval shows the area being treated.

  3. 3

    Lower the redness threshold if any red is left in the pupil, or raise it if skin or lips inside the oval start losing colour.

  4. 4

    Adjust the edge feather so the correction blends into the surrounding face, and pull the strength back if the pupils look too flat.

  5. 5

    Click Download PNG to save the corrected photo at full resolution.

About the Red Eye Remover

Red eye happens when a flash fires close to the lens and lights up the blood vessels at the back of the retina. The fix is not to paint over the pupil but to identify the pixels that are actually red: those where the red channel dominates green and blue by a clear margin and the colour is saturated enough to be red rather than a bright grey.

You drag an oval over the eyes and only pixels inside it that pass both tests have their red channel pulled down to the average of green and blue. That leaves the white catchlight highlight untouched — it is bright but not saturated — so the eye keeps its life instead of turning into a dead grey disc.

The correction fades to nothing at the edge of the oval, so a slightly generous selection blends in rather than leaving a visible patch. The preview updates as you drag, and every pixel is processed in your own browser — the photo is never uploaded.

Frequently asked questions

What causes red eye in flash photos?

When a flash sits close to the lens, its light bounces off the blood-rich retina at the back of the eye and straight back into the camera. The pupil is wide open in the dark, so the reflection fills it and the eye photographs bright red.

Why does the correction only apply inside the box I drag?

Red lips, red clothing and warm skin tones all pass the same redness test that pupils do. Confining the fix to a small oval around the eyes is what keeps everything else in the photo untouched, and the count of corrected pixels tells you how much was changed.

Will this turn the pupils flat grey?

It should not. Only the red channel is pulled down to the green and blue average, so the pupil keeps its own brightness variation, and the bright catchlight fails the saturation test entirely and is left alone. Reduce the strength if the result still looks too flat.

Some red is still left around the pupil — what do I change?

Lower the redness threshold so more marginal pixels qualify, and lower the minimum saturation so the paler ring at the pupil's edge is included too. Raise the edge feather if the treated area is starting to show as a hard-edged patch.

Does it work on animal eyes?

Not usually. Cats and dogs have a reflective layer behind the retina that makes their eyes flash green, yellow or blue rather than red, so a red-channel test finds nothing. This tool is built for human red-eye specifically.

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