Image Channel Mixer
Rebuild the red, green and blue channels of an image from a 3x3 mixing matrix. Each row defines one output channel as a weighted sum of the input red, green and blue, so you can swap channels, create custom black and white conversions, simulate infrared looks or correct strong color casts. Values from -10 to 10 are accepted and the result is clipped to the valid range.
Frequently asked questions
How do I write the mixing matrix?
Enter nine numbers, three per row, separated by spaces, commas or line breaks. The first row produces the output red, the second the output green and the third the output blue, and the three numbers in each row are the weights of the input red, green and blue. The default 1 0 0 / 0 1 0 / 0 0 1 leaves the image unchanged.
How do I swap the red and blue channels?
Use the matrix 0 0 1 / 0 1 0 / 1 0 0. The output red then takes the input blue and the output blue takes the input red, while green stays the same. Skies turn orange and warm skin turns blue, a popular surreal effect.
Can I make a custom black and white conversion?
Yes, repeat the same row three times so every output channel receives the same mix. For example 0.3 0.59 0.11 in all three rows gives a classic luminance conversion, while 0.8 0.2 0 in all rows mimics a red filter that darkens blue skies. Keep the weights summing to about 1 to preserve brightness.
What happens if the weights add up to more than 1?
The output channel gets brighter, and any value above 255 is clipped to white. Weights that sum to less than 1 darken the channel. Negative weights subtract a channel and are useful for stronger color separation.
What range of numbers is allowed?
Each of the nine values must be between -10 and 10, and decimals such as 0.25 are fine. The matrix must contain exactly nine numbers. Anything else is rejected with a message before the image is processed.
How can I fake an infrared photo?
A common starting point is 0 0 1 / 0 1 0 / 1 0 0 combined with a later levels or contrast boost, or a stronger mix such as -0.5 1.5 0 / 0 1 0 / 0 0 1 that makes foliage glow. Experiment with small changes, because the effect depends strongly on how much green the scene contains.
Does the mixer keep transparency?
Yes, the matrix only touches the red, green and blue channels and the alpha channel is carried over unchanged. Grayscale uploads are converted to RGB first so all three output channels can differ. The result is saved as PNG.
Which formats and sizes are supported?
Upload JPEG, PNG, GIF, WebP, TIFF or AVIF files up to 5 MB. Images wider or taller than 4000 pixels are scaled down to fit, and animated files use their first frame. The output is a lossless PNG.
What engine applies the matrix?
The tool uses the recombination operation of the sharp image library, which runs on libvips and multiplies every pixel by the matrix in one pass. The calculation is deterministic, so the same matrix always gives the same file.
When should I use the channel mixer instead of a color adjustment?
Use the mixer when you need control over how channels feed into each other, such as channel swaps, cross talk or a black and white conversion with a specific filter response. For simple changes to hue, saturation or brightness, the Image Color Adjust tool is quicker.