Lighten a dark photo by a set percentage, keeping colours saturated or fading them to pastel. Live preview, batch, and the file stays on your device.
Moves every pixel towards white by the percentage you choose. With Keep colours on, only the lightness component of each pixel rises, so a navy jacket becomes a lighter blue rather than a greyish one. With it off, the same amount is added to red, green and blue, which lifts faster and pulls colours towards pastel and then white, useful for a faded watermark-style background. Nothing clever happens to contrast; the tones simply slide up together.
A photo of a hand-drawn sketch on cream paper came out dark, with the paper at pixel value 150. Lightening by 35% with Keep colours off adds about 90 to every channel, so the paper reaches 240 and reads as white, while the pencil lines move from 40 to 130 and stay clearly visible. For a dim portrait, 20% with Keep colours on lifts skin from 95 to about 145 and keeps its warmth; the same 20% with the option off would make the face look slightly chalky.
Use it for scans and photographed documents, for dim indoor shots that need a gentle lift, and for making a busy image quiet enough to sit behind text. If the picture is underexposed rather than just dark, Change Exposure gives a more photographic result because it scales rather than adds. If the shadows are the only problem, Adjust Gamma lifts them without pushing the highlights to white. And when the goal is a darker version, Darken Image is the mirror of this tool.
Lightness runs from 0 to 100 percent; 100 is a blank white page, and the chips mark the values people usually want. Keep colours switches between an HSL lightness shift, which keeps saturation, and a plain RGB addition, which washes colours out on purpose. For a background image behind dark text, 40 to 60 percent with the option off is the usual range. Output format and quality are in the Output section; Batch mode applies one setting to a folder.
Why do the whites lose detail? Adding to a value that is already near 255 clips it at white. That is expected for a background fade. For a photo you want to keep, use a smaller percentage or switch to Change Exposure or Adjust Gamma.
Keep colours on or off for a text background? Off. It fades colours towards pastel, which reduces the visual competition with your text. Leave it on when you want the photo to stay a photo.
Can I lighten many photos at once? Yes. Turn on Batch mode or drop several files; each gets the same lightness and you download a ZIP.
Is anything uploaded? No. Everything runs in your browser on your own device and works with the network off.