Bluework is based on redwork, only blue threads rather red are used. Confusingly, bluework is sometimes known as blue redwork.
Bluework and redwork are a form of embroidery which uses only a single colour. It became popular in the early nineteenth century when at that point only red dye that was truly colourfast. Later, as dyeing processes improved other colours, including blue, were used for this technique.
Typically, bluework consists of simple outline designs based on simple stitches, primarily backstitch.