It depends on how much of which colour I've got to wash.
Black, white, pink/beige/flesh, green, blue, grey etc.
If there's not a lot of grey, then I throw the greys and blacks together, if there's a lot of greys, they go into their own wash.
I'm a sucker for all the wash stuff. Darks detergent, dark sheets, colour catchers, whites detergents, colours and whites stain removers, delicates detergent, hand wash detergent, little ultra white sachets as well as pre-wash sprays and those squirty bottles with bristly heads to rub into any stains.
I don't so much do the laundry as commit acts of chemical warfare....😳