Masterclass of an exhibition: Impressionists on Paper, at the RA, reviewed

Viewers have different relationships with small pictures, or perhaps it’s the other way round: small pictures have different relationships with them. A big picture clamours for attention; a small picture you have to lean in to hear.

No picture is more intimate than a drawing, and none brings you closer to the artist’s hand. A drawing can’t lie; it wears its facture on its sleeve. If you look closely, you can work out how it was made and even track the artist’s changes of direction. You can see, for instance, how Van Gogh launched into ‘The Fortifications of Paris with Houses’ (1887) in watercolour, then fortified the fortifications with gouache and chalk. A graphic artist by nature, he was at sea with watercolour washes. The thesis of this once-in-a-lifetime show of 77 drawings – 46 from private collections and more than half never shown before in London – is that modern drawing began with the impressionists.