1. Van Gogh was looking for matt effects; see for instance letter 583.

2. Sunflowers in a vase (F 454 / JH 1562 ). In this identification we are following Van Tilborgh and Hendriks 2001, pp. 21-22. Van Gogh added the small bloom at lower left later – this explains why he refers here to ‘14 flowers’.

3. Quinces, lemons, pears and grapes (F 383 / JH 1339 ).

4. F 454 measures 93 x 73 cm; F 383 measures 48.5 x 65 cm.

5. Edouard Manet, Vase of peonies on a pedestal, 1864 (Paris, Musée d’Orsay). Ill. 227 . Vincent and Theo saw this work on 5 June 1886 during the sale of John Saulnier’s collection in the Hôtel Drouot in Paris, where it was listed as cat. no. 62, Vase of flowers by Paul [sic] Manet. See auct. cat. Paris 1886.

6. Besides the work referred to in n. 2, Van Gogh means the three paintings that he said he was working on in letter 666: Sunflowers in a vase (F 453 / JH 1559 ), Sunflowers in a vase (F 459 / JH 1560 ) and Sunflowers in a vase (F 456 / JH 1561 ).

7. The painting in question is Sunflowers in a vase (F 459 / JH 1560 ). Van Gogh wrote ‘soleils’ (suns) rather than ‘tournesols’ (sunflowers); cf. for the association of sunflowers, sun and the south of France, and in connection with this choice of words: Dorn 1990, pp. 116-117.

Van Gogh may have got the concept of ‘haloing’ from Charles Blanc, who wrote in his Grammaire des arts du dessin: ‘Putting a particular colour on a canvas, said Mr Chevreul, doesn’t just tint everything that the brush touches with this colour, but also provides complementary colour to the surrounding area, so a red circle is surrounded by a slight green halo which becomes fainter as it spreads out; an orange circle is surrounded by a blue halo; a yellow circle is surrounded by a violet halo..... and vice versa.’ (Mettre une couleur sur une toile, dit M. Chevreul, ce n’est pas seulement teindre de cette couleur tout ce qu’a touché le pinceau, c’est encore colorer de la complémentaire l’espace environnant; ainsi un cercle rouge est entouré d’une légère auréole verte, qui va s’affaiblissant à mesure qu’elle s’éloigne; un cercle orangé est entouré d’une auréole bleue; un cercle jaune est entouré d’une auréole violette..... et réciproquement) (see Blanc 1870, p. 606).