# Image Levels

Adjust the tonal range of a photo the way the Levels dialog in a desktop editor does. Set the input black and white points to clip dull shadows and highlights, move the gamma to brighten or darken the midtones, and limit the output range, for all channels at once or for red, green or blue alone. Ideal for fixing flat scans, washed out photos and color casts.

## Frequently asked questions

### What do the input black and white points do?

Every value at or below the input black point becomes the output black, and every value at or above the input white point becomes the output white. The values in between are stretched across the full output range, which adds contrast to flat or hazy images. The black point must stay lower than the white point.

### How does the gamma setting change the image?

Gamma bends the curve between the black and white points without moving them. Values above 1 brighten the midtones and values below 1 darken them, while pure black and pure white stay where they are. The accepted range is 0.1 to 10, and 1 leaves the midtones unchanged.

### What are the output black and white points for?

They set the darkest and brightest values the result may contain. Raising the output black to around 20 gives a softer, printed look, and lowering the output white keeps highlights from reaching pure white. Setting the output black above the output white inverts the tones.

### Can I adjust a single color channel?

Yes, choose red, green or blue in the channel menu to apply the levels to that channel only, leaving the other two untouched. This is the classic way to remove a color cast, for example by lowering the blue white point of a photo that looks too cold. A grayscale upload is converted to RGB first so the single channel can be changed.

### How do I fix a washed out or foggy photo?

Look for the darkest and brightest areas that should be black and white, then raise the input black point to roughly the value of the haze and lower the input white point slightly. Values such as 30 and 230 already remove most fog. Fine tune the midtones afterwards with gamma.

### Does the tool keep transparency?

Yes, the alpha channel is copied unchanged, so transparent PNG, WebP or GIF areas stay transparent. Only the color values are remapped. The result is saved as a PNG so the transparency survives.

### Which file formats can I upload?

You can upload JPEG, PNG, GIF, WebP, TIFF and AVIF images up to 5 MB. Animated GIF and WebP files are reduced to their first frame. The adjusted image is always downloaded as a lossless PNG.

### Is there a size limit for the image dimensions?

Images larger than 4000 pixels on a side are scaled down proportionally to fit within 4000 pixels before the adjustment. Smaller images keep their exact dimensions. Extremely large pixel counts are rejected.

### How precise is the adjustment?

The tool builds a lookup table for all 256 values of each 8-bit channel and applies it to every pixel, so the result is exact and repeatable. Running the same settings on the same file always gives identical output. No resampling or compression is applied apart from the PNG encoding.

### How is Levels different from brightness or contrast tools?

Brightness and contrast move all tones by one rule, while Levels lets you pin the exact values that become black and white and shape the midtones separately. That makes it more precise for correcting exposure and casts. It is the same control photographers use before reaching for curves.

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