Using a single color can add drama by simplifying, and thus emphasizing the motif.
During the 19th century, the cost of paying a highly-trained and talented artist to create designs for textiles was less than the cost of using complicated printing techniques that required expensive mordants and dyes.
A finely-detailed pattern would be commissioned from an artist for a monochromatic motif. The design was then engraved on printing plates or rollers. The rollers could be used for many printing runs which saved production costs and the use of a single color dye made further cost savings.
The first example below of a monochromatic print is the charming toile based on neoclassical motifs and includes cherubs, squirrels, parrots and butterflies. The second example is a 19th century red on white, but with a complicated tonal pattern that required more than one pass of the printing plate.
The motif becomes all-important as can be seen in these examples. The blue on white and the red on white are both 19th century prints. Both of these prints are on a fancier cotton with a woven stripe pattern. The green on white is a 1930s stylized motif on a plain cotton.
In the next pair, one color printed on white, the designer has left the motif white and has used the color on the background instead. The orange example is a 19th century fabric and the green is from early 20th century.