SDD,
The color you see is dependent on the wavelengths of light hitting the object. For example if you shine a “white light” which consists of Red, Green and Blue light onto a surface that absorbs red light the surface will reflect back green and blue and you will see the surface as purple. (Green + blue= purple I think) if you use a plastic filter that only lets green light through to the surface you will see that surface as green. No contradiction at all.