Black and White Conversion
Turning a colour image into monochrome by mapping each colour to a chosen grey value.
In depth
The important decision is how each colour translates, since colours of similar brightness collapse into identical greys unless they are separated deliberately. A dedicated conversion offers a slider per colour band, so a red barn can be darkened and a blue sky deepened independently — exactly what coloured filters achieved on panchromatic film.
Examples in practice
Dropping the blue channel's luminance in conversion darkens the sky dramatically, mimicking a red filter on film.