Here a porcelain palette plate (from @V_and_A), made in Paris 1810-20, so that a painter could gauge the eventual colour of enamels after firing.

A functional object that inadvertently ends up looking like it was made by the Bauhaus.

Interesting to compare with a later and more formal, but to my eyes much less beautiful, example of the same concept from later in the century:

A colleague sends me a third, much more elaborate iteration of a palette plate, from the Frankenthal Porcelain Factory, 1775:

& another palette plate, this time from Sevres (1865)

Now this example I think absolutely ravishing, like a Sonia Delauney, from Chantilly, probably 1920s.

Royal Copenhagen Porcelain Factory, probably 1930s.

This one is by the Staffordshire potter Joseph P Emery (1899)

A heavenly early-20th century set, from the Schumann factory, Arzberg.

The labels of the colours are for some reason in English, & include lovely names such as violet of iron, rose pompadour, golden prawn, Berlin rose, light Dresden lilac, deep heliotrope.

An example by another Staffordshire manufacturer, H&R Johnson Tiles Ltd, with a transfer print of Phoenix Rising from the Ashes in the middle.

An early 20th century example by Theodore Haviland, Limoges.

Porzellan Manufaktur Nymphenburg, 1948.

A related object in the Bayerisches Nationalmuseum; the 'Arcanum Case' of the Frankenthal Porcelain Factory (1775), for what was still a highly secretive industry, containing plans of the refining machines & kilns, and 62 glazed porcelain sample discs.

Hancock & Son, Worcester:

A scalloped plate, also by Theodore Haviland, Limoges.

An elaborate goblet & saucer, from the Imperial Porcelain Manufactory, Vienna (1804).