Primary pigment (paint) colours are:

Red blue and yellow

These paint colours mix in different proportions to make all colours. They can then be tinted or shaded with white and black to add different dimensions to each colour.

We see different paint colours when some light colours are absorbed into a surface and some are reflected to our eye.

As you mix the colours together they become duller. They are 'toned' down.

If you mix equal proportions of all of the primary colours together you make the perfect grey.