Image Black and White Point Adjustment

Set an image’s black and white points to stretch RGB levels. Dimensions stay unchanged. Processing takes place locally in your browser.

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Image Black and White Point Adjustment

Set an image’s black and white points to stretch RGB levels. Dimensions stay unchanged.

Shadow defaults to 20 and is limited to 0–254; highlight defaults to 235 and is limited to shadow+1–255. A highlight at or below shadow, including 0, uses shadow+1. Empty shadow/highlight inputs use 0/255. The same mapping applies to each RGB channel; alpha is unchanged.

output = (channel − shadow) × 255 / (highlight − shadow)
≤ shadow → 0; ≥ highlight → 255; alpha → alpha

Narrowing the range increases contrast and can discard tonal detail in the exported copy. Lowering the white point brightens intermediate values; raising the black point darkens them. This does not crop dimensions or recover lost detail. No histogram, eyedropper, automatic levels or separate channel controls. Browser-readable images: at most 25 MiB and 24,000,000 pixels. PNG export may lose metadata and animation; GIF uses the frame decoded by the browser. Keep the original.

Processing takes place locally in your browser.

How to use

Image Black and White Point Adjustment

Select, drop or paste one image. Enter the two levels, generate the result and download PNG. Generate again after editing; every result uses the original image.

20 / 235: RGB(20,128,235) → RGB(0,128,255)
0 / 255: RGB(0,100,255) → RGB(0,100,255)
100 / 0 → 100 / 101: RGB(100,150,200) → RGB(0,255,255)

Free calculators, converters and browser tools

Image Black and White Point Adjustment: Set an image’s black and white points to stretch RGB levels. Dimensions stay unchanged.
Batch Image Levels — Black and White Points: Set shared black and white points for up to 30 images, stretch RGB levels locally and download PNGs at the original dimensions.