Josiah Spode I is credited with having perfected the technique of underglaze printing on blue on earthenware in about 1784. Additional underglaze colours were not to be successfully produced until nearly forty years later. The B series of Spode patterns, a numbering system used for underglaze designs, was introduced in about 1822.

Prior to this, colour printing other than blue was restricted. Colour was achieved by overglaze enamel decoration or hand coloured blue, brown or black prints. Black, purple and ochre were available but were not popular colours for ceramic decoration. It was only after much experimentation that new, mainly chrome based, colours were introduced that could withstand the high temperature glost firing required for underglaze decoration.

The new colours 'bonded' less well with the glaze than the blue; this meant that the appearance was less translucent and luscious but at the same time it led to a sharper image. Chrome Green which contains no cobalt gives a particularly sharp image as can be seen in the clarity of detail on items decorated with the Byron Views pattern. It was the most successful colour after blue. Chrome Green produced by the use of iron chromate, was introduced in c1822 followed by a series of other colours including brown, puce, orange and a blue-grey known as Paynes Grey. A common colour, particularly for sheet patterns is a khaki green known as 'Pigmuck Green' (for obvious reasons!), it is thought to have been made from the dregs of other unused printing colours. Underglaze pink was introduced around 1833 by adding a small amount of tin oxide to iron chromate; early examples are rare but the colour has been reintroduced several times in the history of the company.

Spode was responsible for the first two-colour printing technique. The process, which was introduced around 1824 involved the use of a resist substance known as 'ackey' (the Potteries term for sticky and dirty). This protected a hardened-on print before applying an all-over sheet pattern. This allowed an image to be placed within a printed background of another colour. Tumbledown Dick on Marble Sheet is a classic example of this technique.

Many more dinner plates were made than any other shape but printed patterns can be seen on all shapes of table ware as well as toilet ware including leg baths, foot baths, chamber pots and bidets. Dessert wares were more often handpainted and gilded as they were subjected to less wear. Underglaze decoration for dinnerwares was popular because the design was protected under the glaze from the sharp steel cutlery of the time.

Further general reading: Robert Copeland; Spode and Copeland Marks and Other Relevant Intelligence: Studio Vista. ISBN 0-289-80172-9