I’m going to take the opportunity to get at the Constable palette I’d mentioned. This is taken from Tate Publishing’s John Constable: The Great Landscapes–a really wonderful and highly recommended book. There’s also a John Gage essay in it. Gage wrote the masterful Color in Turner, which I also want to get into, particularly where he covers Turner’s influences, including notes Turner made on specific Old Master paintings he was studying.
One of Constable’s surviving palettes is covered with original impasted blobs of smeared paint [pictured in the book itself] and a darkened brown substance that is probably a spilled medium or varnish. Analysis of the materials was first carried out at the Tate for the Paint and Painting exhibition; the catalogue lists vermilion, Emerald green, chrome yellow, and madder as having been identified. Further pigment analysis by Sarah Cove and Rachel Grout has also identified Patent yellow (lead oxychloride), cobalt blue, lead white, a bright scarlet (possibly a commercially prepared mixture of vermilion and the organic red lake pigment madder), Mars yellow (synthetic iron oxide), black (possibly bone black) and various red, brown and orange earths. These were found in a variety of mediums, including linseed oil mixed with pine resin, and either walnut oil or a mixture of poppy and linseed oils with a lot of pine resin mixed in. The spilled medium is a resin varnish, probably damar or mastic, with a small addition of a ‘drying’ oil. Sarah Cove has identified these pigments and mediums in the ‘finishing’ layers of Constable’s late works, c. 1828-37. and they closely correspond to those identified in the metal paint box. The pigments include both translucent colors that were used for final glazing in a lush, glossy, slow-drying linseed oil/pine resin medium, and opaque yellows and whites, bound in poppy oil, probably with the addition of egg, to create the crisp highlights used to add the distinctive ‘sparkle’ to Constable’s exhibited paintings. Cobalt blue is particularly significant as it is rarely found in Constable’s oils, though it has been identified in some works of the 1820s….
There is also a list of contents of the a paint box:
The glass phial with cork stopper contains the powdered blue-glass pigment smalt, some of which has spilled out. Smalt was routinely used by Constable in conjunction with the expensive blue pigment natural ultramarine, probably as an ‘extender’ to make the color go further. Similar phials containing two shades of ultramarine are in Constable’s other surviving paint box. The white stone is a piece of gypsum (mainly calcium sulphate, containing a small proportion of natural chalk), which may be a lump of wall plaster that served a variety of purposes: roughening the surface of paper or canvas or rubbing down grounds; drawing, like ‘chalk’; or powdered up and used as an extender to make colors more translucent whilst thickening the paint. There are eleven bladders of paint in the box, some with illegible paper labels… The bladders contain the following: verdigris; a mixed yellow-brown glaze containing a yellow lake with small additions of black, vermillion, patent yellow and orange earths; chrome yellow (lead chromate); a blue-green containing verdigris and Prussian blue; a transparent orange iron oxide (Mars orange); an orangey-brown mixture of earths and black; umber; a dark red-brown mixture of umber and vermilion; Emerald green (copper aceto-arsinate). These are both pure pigments and mixtures that have been purchased under proprietary names describing the color rather than the constituent pigments. The paint in the bladders is primarily bound with slow-drying poppy oil… sometimes with additions of thickened linseed and possibly pine resin.,…The bladders are covered in bright specks of dried paint that were also analyzed to discover Constable’s working mixtures. These include the pigments listed above, together with lead white, bone brown/black, synthetic red and yellow iron oxides (Mars colors) and two different red ‘lakes’. The pigment splashes contained a mixture of the mediums found in the bladders together with the additives: zinc sulphate driers in poppy oil, lead-based driers in linseed oil, mastic varnish, egg yolk, beeswax and pine resin.