I wasn't talking about blue green or yellow green. those have green in them. If you mix blue and yellow light your brain 'interprets' it as white. It cannot sense blue yellow.

In the USA yellow signs are used for safety warnings.

Red is ONLY used for stop, green is used for directions, and blue is used for info, white is used for legal notices, but yellow is safety, when visibility is most required.

inks and pigments act different, I'm only talking about the light wavelengths.