Canon EOS 90D DSLR Camera with 18-135mm Lens - Manual (Page 223)

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White Balance Settings
White Balance
To the human eye, a white object looks white regardless of the type of
lighting. With a digital camera, the white for color correction basis is decided
depending on the color temperature of the illumination, and then the color
is adjusted with software to make the white areas look white. With this
function, you can take the pictures with natural color tones.