The Caslon type foundry was a type foundry in London which cast and sold metal type. It was founded by the punchcutter and typefounder William Caslon I, probably in 1720. For most of its history it was based at Chiswell Street, Islington, was the oldest type foundry in London, and the most prestigious.

A reverse-contrast or reverse-stress letterform is a design in which the stress is reversed from the norm: a typeface or custom lettering where the horizontal lines are the thickest. This is the reverse of the vertical lines being the same width or thicker than horizontals, which is normal in Latin-alphabet writing and especially printing. The result is a dramatic effect, in which the letters seem to have been printed the wrong way round. The style invented in the early nineteenth century as attention-grabbing novelty display designs. Modern font designer Peter Biľak, who has created a design in the genre, has described them as "a dirty trick to create freakish letterforms that stood out."