Van Gogh's sunflowers are painted with "three chrome yellows, yellow ochre and Veronese green and nothing else", thus creating a powerful and refined image with only variations of a single color. This use of a single color was revolutionary. Two hues of luminous yellow were used next to each other and with cross-hatching in the background, thus reinforcing the painting’s luminosity.
The sunflower paintings had a special significance for Van Gogh. He hung the first two in the room of his friend, the painter Paul Gauguin, who came to live with him for a while in Arles.
"Supposing that the two canvases of sunflowers have certain qualities of colour, and then also that they express an idea symbolizing ‘gratitude’." - Vincent van Gogh to Albert Aurier. Saint-Remy-De-Provence, Monday 10 February 1890.