With the brush we merely tint, while the imagination alone produces colour.

The remark contrasts the physical act of painting with the mental act that gives a work its true vividness. A brush can apply pigment—mere “tint”—but the sense of living colour (atmosphere, emotional temperature, dramatic unity) is created by the artist’s imagination: the capacity to select, intensify, and harmonize what is seen into a compelling vision. Read this way, “colour” is not only a technical property but an expressive one, tied to invention and feeling rather than to materials. The statement aligns with Romantic-era ideas that art’s power lies in inner conception and imaginative transformation, not in mechanical finish alone.