Canon EOS 4000D Instruction Manual page 78

Shooting with Ambience Selection
(7) Brighter
The picture will look brighter.
(8) Darker
The picture will look darker.
(9) Monochrome
The picture will be monochrome. You can select the monochrome
color to be blue, black and white, or sepia. When [Monochrome] is
selected, <0> will appear in the viewfinder.
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