Joseph Mallord William Turner

This study on white wove paper was initially worked with very pale watercolour washes that were applied broadly horizontally to soaked paper, and allowed or encouraged to spread out into shapes suggestive of a mountain landscape. Later washes, equally pale, were applied in pink to the centre of the page, and in blue in the lower third, with the paper slightly less wet to permit more control of the final spread of each colour. When the paper was dry, some of the broad colour divisions were lightly outlined with graphite pencil to define the mountains. Thereafter, the study was developed with more localised and sometimes darker watercolour washes, interspersed with applications of a white gouache that has now discoloured, as if created by the more conventional technique of pencil sketching followed by the application of coloured washes that loosely followed the sketched design. Turner has used this more experimental, colour-led process in sketches of Venice, dated to the previous year, for example in The Redentore and the Western Part of the Giudecca Canal (Tate D32146; Turner Bequest CCCXVI 9), albeit less freely before he began to outline building in pencil. In this study, there is an impression of improvisation around accidental effects, rather than repeated working to achieve an imagined end.

The white gouache has become buff-coloured, and there is a halo round each area of gouache, noticeable on close examination by eye, but more clearly in ultraviolet light, since it fluoresces. This suggests that the gouache is made with an oil medium. This is one of the very few Turner watercolours where white/off-white magnesium carbonate has been identified in an oil-based gouache applied to paper, though the presence of oil medium has been suspected in other cases which also have halos of yellow/brown round each brush-stroke of gouache. Magnesium carbonate was a known alternative material to chalk, here combined with a little black pigment, and with white barium sulphate, used by this time (by the manufacturer) to extend other white pigments. Both materials have been found separately though combined with others among Turner’s studio pigments, but not previously in any of his watercolours. Here, this white material is less substantial, and less dominating in the composition, than when Turner used lead white in gum for his gouache. But the magnesium carbonate and barium sulphate mixture probably looked like a very dense white as a dry powder pigment before it was made into a paint. It is its use with oil medium that has rendered it more transparent, and the ageing of the oil medium that has made it turn buff colour instead of the pale grey Turner intended to use when he mixed in some black.