Subtractive color mixing is used in

In subtractive mixing, each coloured material absorbs (subtracts) some colours of white light. Only the remaining colours reach your eyes.

Paints and dyes work like this. Mixing more of them absorbs more light, so the result gets darker.

Televisions and lasers produce light directly. Traffic lights give out coloured light. Light sources use additive mixing, not subtractive.