[1] According to Michael Gibson [2] there were 16 potteries in Sunderland of which 7 are known to have produced lustrewares (alongside conventional wares of various types) in the nineteenth century.
Many are not marked, and are hard or impossible to distinguish from similar wares made in Staffordshire pottery, as well as Newcastle upon Tyne and North Shields, so to some extent Sunderland has become a term for the style, rather than a specific indication of origin.
[3] The Sunderland factories mostly made fairly cheap and popular pieces, many of them plaques, especially rectangular ones with "picture frame" edges, and an image of inscription in the central panel; these are usually in the characteristic pink colour.
These might be a transfer-printed image of a ship, celebrity, or building, or a painted personal inscription (known as presentation pieces).
Typical pieces are plaques with moral or religious images and texts, and jugs featuring a design incorporating the bridge over the River Wear, or various heraldic - especially Masonic - devices.