The colour of a prisoner's uniform determines his or her category.

Clean prisoner uniform

A clean prisoner uniform.

Red prisoner uniforms are for high-risk prisoners.

Orange prisoner uniforms are for medium-risk prisoners.

Grey prisoner uniforms are for low-risk prisoners.

Dark red prisoner uniforms are for Supermax prisoners.

Black prisoner uniforms are for Death Row prisoners.

Yellow prisoner uniforms are for Protective Custody prisoners.

Prisoner Uniforms are purchased automatically when you fail to upkeep them through laundry. Prisoners will change into a clean uniform (if available) after they shower, lowering the clothing need.
Dirty prisoner uniform

A dirty prisoner uniform.