Image Exposure Adjuster
Fix photos that came out too dark or too bright. The exposure adjuster works in stops (EV), the unit photographers use: +1 EV doubles the light, −1 halves it. The change is applied in linear light, the way a camera sensor records it, so colours and contrast stay natural, and a soft shoulder keeps bright areas from turning white. Auto exposure brings the photo’s middle tones to the standard middle grey.
- Files stay on your device
- No sign-up
- Free to use
Exposure
One stop (1 EV) doubles or halves the light, like opening the aperture one step. The change is made in linear light, as a camera would, so colours stay natural.
Output
How to use Image Exposure Adjuster
- Drop one or more photos onto the page.
- Move the exposure slider or click Auto exposure.
- Keep highlight protection on unless you want hard highlights.
- Download the corrected photos.
Image Exposure Adjuster features
Photographic stops
−3 to +3 EV in 0.1 steps.
Linear light
Behaves like changing the camera exposure.
Highlight protection
Soft shoulder instead of hard clipping.
Auto exposure
Targets 18% middle grey.
Batch
Apply the same settings to up to 50 images.
Private
Processed in your browser; nothing is uploaded.
When to use Image Exposure Adjuster
- Rescuing underexposed indoor and evening photos.
- Toning down overexposed beach and snow shots.
- Matching the brightness of a series.
- Preparing scans of dark prints.
Image Exposure Adjuster FAQ
How is exposure different from brightness?
Brightness tools usually add or multiply the stored pixel values, which are gamma-encoded. Exposure multiplies the actual light in linear space, as a longer shutter time would. Shadows and highlights respond in the same proportions as in a real camera.
What does +1 EV mean?
One stop more light: twice as much. +2 EV is four times, −1 EV half.
Can it recover blown-out highlights?
No. Areas that are pure white in the file have no detail left. Lowering exposure turns them grey, not detailed. Use the highlight adjuster to recover areas that are bright but not clipped.
How does Auto exposure work?
It measures the median brightness and calculates the exposure change that brings it to middle grey (18% reflectance), the reference exposure meters use.
Will brightening increase noise?
Yes, like raising ISO. Use the Image Noise Reducer afterwards if needed.
Are my photos uploaded?
No. The images are processed in your browser and never leave your device.
Exposure in linear light
Image files store brightness on a curved scale, the sRGB gamma curve, because our eyes are more sensitive to differences in dark tones than in bright ones. This is efficient for storage but awkward for editing: doubling a stored value does not double the light. A pixel at 50% grey in the file actually represents about 21% of the maximum light.
The exposure adjuster converts every value to linear light first, multiplies by two to the power of the EV value, and converts back. The result is the same as having exposed the photo longer or shorter in the camera: the relationship between tones is preserved, and colours do not shift towards grey or become oversaturated as with simple brightness sliders.
Brightening a photo pushes bright tones beyond the maximum. Without protection they clip to pure white and lose all detail. The highlight protection compresses values above 80% of the range with a smooth curve – a shoulder, as in film – so bright skies and lamps keep some gradation.
Auto exposure uses the median brightness of the photo, which is robust against a few very bright or dark areas. It assumes that the scene should average to middle grey, the same assumption a camera’s light meter makes. For scenes that are naturally bright (snow) or dark (night), adjust the result by hand.
Your photos are processed locally, so nothing is uploaded.