Image Brightness and Contrast
Tune a local image with live brightness and contrast controls.
Adjust image tones with direct pixel math
Brightness shifts every red, green, and blue channel by the same amount, while contrast expands or compresses channel differences around the midpoint. This tool decodes a selected image into a canvas, keeps an untouched pixel copy, and recalculates the preview from that original whenever a slider moves. Reapplying from the source avoids accumulating rounding damage as settings are adjusted back and forth.
At the default settings, brightness and contrast are both zero, so a source pixel with channels 100, 150, and 200 remains unchanged. Raising brightness to 10 with zero contrast changes those channels to 110, 160, and 210. The output is clamped from zero through 255, and the download button exports the currently displayed canvas as a PNG. A built-in color field provides an immediate preview before a file is selected.
Your selected image stays on the device
The image file, decoded pixels, and generated PNG remain in your browser. Large source images are scaled down to fit a 1600 by 1200 processing boundary, which keeps interaction responsive and also means this page is not an archival-resolution editor. For print color, RAW development, selective masks, or nondestructive professional adjustments, use software with color profiles, higher bit depth, and an explicit export workflow.
Frequently Asked Questions
Does the image leave my device?
No. The selected file is decoded and processed in the browser without an upload.
What format does the download use?
The adjusted canvas is exported as a PNG file.
How is contrast applied?
Each RGB channel is transformed around the midpoint using the selected contrast factor, then brightness is added and values are clamped.
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