Seeing like an artist

Edmund Gosse found John Singer Sargent painting one day "in a white-washed farm-yard, into which I strolled for his company, wearing no hat under the cloudless blue sky. As I approached him, Sargent looked at me, gave a convulsive plunge in the air with his brush, and said "Oh! what lovely lilac hair, no one ever saw such beautiful lilac hair!" The blue sky reflected on my sleek dun locks, which no one had ever thought "beautiful" before, had glazed them with colour.... The real colour of the hair was nothing, it existed only in the violet varnish which a single step into the shade would destroy forever."