In this work Degas has made use of some contemporary ways of making art. It wasn't just the subject matter that was modern - but the techniques used also had a point to make.
The Monotype and the use of pastel
A monotype, which is the technique Degas used for Women on the Terrace of a Cafe, Evening, does not require engraving. It is a unique print taken from a drawing or painting usually made on a glass or metal plate. The medium is often oil paint or printer's ink.
Here's another image The Cafe Concert, which Degas created from a monotype:
Once the image is made on the receptive surface, the paper or board is pressed onto that surface, manually or with a press. When peeled off the results can be extremely striking and unpredictable.
Degas' addition of pastel to his print, Women on the Terrace of a Cafe, Evening, adds another layer of spontaneous texture to his 'accidental' creation. The very technique itself seems to reflect the movement and fragmentation of the bustling boulevard. The addition of pastel to the work incorporates the old and the new, and the swiftness and uncertainty of this medium may also be some kind of a moral statement.