About

Color inversion transforms every pixel to its complementary value on the 0 - 255 scale. A pixel with value V becomes 255 − V. Black (0) becomes white (255). White becomes black. Grayscale images produce photographic negatives. This operation is self-inverse: applying it twice restores the original image exactly.

Incorrect inversion ruins archival scans, medical imaging analysis, and print preparation. Film negatives require precise reversal to produce accurate positives. This tool processes images entirely in your browser using the Canvas API. No server upload means no compression artifacts, no privacy concerns, and no file size limits beyond your device memory. The luminance-weighted grayscale conversion uses ITU-R BT.601 coefficients for perceptually accurate results.

Formulas

The inversion formula operates on each color channel independently. For an 8-bit image with values ranging from 0 to 255:

V′ = 255 − V

For RGB images, this applies to each channel:

R′ = 255 − R
G′ = 255 − G
B′ = 255 − B

For perceptually accurate grayscale conversion before inversion, the ITU-R BT.601 luminance formula applies:

Y = 0.299R + 0.587G + 0.114B

Where V represents any pixel value, V′ is the inverted result, R, G, B are red, green, and blue channel values, and Y is the luminance (grayscale) value. The alpha channel remains unchanged to preserve transparency.

Reference Data

Original Value	Inverted Value	Visual Result	Use Case
0 (Pure Black)	255 (Pure White)	Complete reversal	Film negative scanning
255 (Pure White)	0 (Pure Black)	Complete reversal	Document inversion
128 (Mid Gray)	127 (Mid Gray)	Near identical	Neutral point reference
64 (Dark Gray)	191 (Light Gray)	Significant lightening	Shadow detail recovery
191 (Light Gray)	64 (Dark Gray)	Significant darkening	Highlight detail recovery
32 (Near Black)	223 (Near White)	Extreme contrast flip	X-ray image processing
223 (Near White)	32 (Near Black)	Extreme contrast flip	Astronomical imaging
100	155	Moderate shift	General photo editing
155	100	Moderate shift	General photo editing
200	55	Light to dark	Print preparation
55	200	Dark to light	Screen optimization
240	15	Near-white to near-black	High-key inversion
15	240	Near-black to near-white	Low-key inversion
180	75	Upper mid to lower mid	Tonal balancing
75	180	Lower mid to upper mid	Tonal balancing

Frequently Asked Questions

RGB inversion transforms each channel independently. Red (255, 0, 0) becomes Cyan (0, 255, 255). For a photographic negative effect on color images, you need to invert in a different color space or convert to grayscale first. This tool offers a "Grayscale First" option that converts to luminance values before inverting, producing results similar to traditional film negatives.

No. The inversion is a lossless mathematical operation performed on raw pixel data in your browser. The output quality depends solely on your chosen export format. PNG preserves exact pixel values. JPEG introduces minor compression artifacts. WebP offers a balance. For archival work, always export as PNG.

The alpha channel (transparency) is preserved unchanged. Only the RGB color values are inverted. A pixel with 50% transparency will maintain that exact transparency level after inversion. This allows you to invert graphics with transparent backgrounds without losing the transparency mask.

The limit is your browser's available memory, typically allowing images up to 50-100 megapixels on modern devices. For images exceeding 2 megapixels, processing occurs in chunks with a progress indicator to prevent browser freezing. Canvas API constraints on some mobile browsers may limit dimensions to approximately 4096 pixels on either axis.

This tool processes the entire image uniformly. For selective inversion, you would need to pre-mask regions in an image editor, export the masked area, invert it here, then composite the result. The inversion formula is deterministic, so you can process the same region multiple times with identical results.

Traditional photographic film has a non-linear response curve (gamma) that differs from digital linear inversion. Film negatives also have an orange color cast from the base material. This tool performs mathematically precise linear inversion. For film emulation, additional gamma correction (typically γ = 2.2) would be required.