Newton subscribed to the doctrine that physical objects do not actually have the colors we ordinarily take them to possess, treating color as a sensation rather than a property of objects.

Evidence

Color (Stanford Encyclopedia of Philosophy) (Stanford Encyclopedia of Philosophy)

XREF: connects to: White is the most inferior of colors of morals of superiority. It follows that whiteness is the lack of characteristics that make a theme and give it its facets of colors. ; Colors are not properties of objects but of perceptual processes, and one proposal identifies them with physical ‘spectral surface reflectance.’ — The Reality of Color Is Perception; Newton states ‘Whiteness and all grey Colours between white and black, may be compounded of Colours, and the whiteness of the Sun’s Light is compounded of all the primary Colours mixt in a due Proportion.’ — The First Book of Opticks. Part II (1704)

Newton states ‘Whiteness and all grey Colours between white and black, may be compounded of Colours, and the whiteness of the Sun’s Light is compounded of all the primary Colours mixt in a due… (similarity 0.90)
White and black are also colors, with Newton himself noting ‘The first of all simple colours is White, though philosophers will not acknowledge either White or Black to be colours.’ (similarity 0.89)
Colors are not properties of objects but of perceptual processes, and one proposal identifies them with physical ‘spectral surface reflectance.’ (similarity 0.86)
Newton’s foundational Opticks encoded whiteness as the standard of light. (similarity 0.84)
There is generally no fixed relation between spectral distribution and perceived color, though a surface does have a determinable color under fixed viewing conditions. (similarity 0.82)
In visual perception a color is almost never seen as it physically is, making color the most relative medium in art. (similarity 0.81)
Philosophers examine whether whiteness is a color at all, distinguishing the physics of spectral reflectance from the perception of color, a divide that determines whether white counts as ‘a… (similarity 0.81)
Spectral reflectance does not determine perceived color, since any achromatic paper can be made to appear any shade of white, gray, or black, the physics of reflectance diverging from color… (similarity 0.80)