Technique and condition
This study in watercolour and gouache on white wove paper is similar in appearance to the better -preserved Mount Pilatus, from Lake Lucerne (Tate D33496; Turner Bequest CCCXXXII 26), which included an unusual gouache mixture of magnesium carbonate and barium sulphate in oil medium, as well as more conventional watercolour washes. The present work has been displayed to too much light in the past, while covered by a window mount. This has caused the paper to turn brown, and may have made the unusual white gouache change even more towards buff. Certainly, it is not very dominant now in Mount Pilatus, though it would once have had more impact. The change is practically irreversible now, except by exposing the whole sheet to light, which is precluded here because that would make the paper discolour more.
Several gums were available in Turner’s era: notably gum arabic and gum tragacanth. The former is today used alone in commercial watercolour paints. The latter could be a practical choice because it does not ‘wash up’. This nineteenth-century term means that a later wash in gum tragacanth, applied to dried paper, would not wet and re-activate an earlier wash as much as would happen when gum arabic alone were used. That makes it very useful for an artist who applies multiple washes, uses plain water for washing out, and generally works his paper extensively, all of which describe Turner’s working methods. A method of chemical analysis called gas chromatography was used, which separates out components of a complex mixture to allow later identification. This was combined with mass spectrometry for more precise identification of the separated components. The result was that the gum used here was a mixture: gum arabic as the largest component, most likely with gum tragacanth added. Comparable mixtures were found in the watercolour blocks in Turner’s travelling watercolour palette (now at the Royal Academy of Arts, London), which proves that he need not have ground the paint himself.