Adjust image brightness — free online tool
Lighten or darken a photo with the Brightness slider, 20 to 180 percent. Worked values at 120 percent, where highlights clip, and when to use Shadows.
The preview will appear here after you select a file.
What to know
Brightness here is a straight multiplier on every color channel. At 120 the value 100 becomes 120, 200 becomes 240 and anything from 213 upward is pushed to 255, which is pure white. At 50 every channel is halved, and the slider bottoms out at 20 percent and tops out at 180.
Because it is a multiplier, a small move goes a long way in bright scenes. A snow shot or a white product on white paper has many pixels already above 200, so even 110 percent flattens fine texture in the brightest areas. When that happens, back the slider off and raise Shadows by +30 or so, which lifts the dark side of the picture and leaves the top end where it was.
Typical uses: a dim indoor photo that wants 115 to 125, a screenshot of a dark interface that you want at about 70 for a calmer slide background, and an image headed for print. Monitors are brighter than paper, so a picture that looks right on screen often prints darker, and many people add 10 to 15 percent before sending it to a printer.
Hold the original button while the preview is on screen to flip between before and after. The export keeps the source format at quality 0.92, and JPG sources are re-encoded once.
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How to use Adjust image brightness — free online tool
- Add the photo that looks too dark.
- Drag the Brightness slider from 100 to 120 and watch the preview.
- If whites look flat, lower it to 112 and raise Shadows to +30 instead.
- Press Apply adjustments and download the lightened copy.
Quick answers
What does brightness 120 do to a pixel value of 100?
It multiplies by 1.2, so 100 becomes 120. A value of 200 becomes 240, and anything above about 212 is clipped to 255.
Why do my whites look flat after raising brightness?
Pixels that reach 255 cannot get brighter and lose their differences from each other. Lower the slider and use Shadows to lift the dark areas instead.
How dark can the slider make a photo?
The minimum is 20 percent, which multiplies every channel by 0.2, so white becomes a dark gray near 51 and the picture is almost black.
Should I brighten a photo before printing it?
Often a little. Screens emit light and paper only reflects it, so 10 to 15 percent extra brightness is a common compensation, but a test print is the only sure check.