Rouart, Denis. Degas: In Search of His Technique. New York: Rizzoli International Publications, 1988.
This book, like Richard Thomson's The Private Degas, is a fantastic source for learning the techniques of Edgar Degas. Unlike The Private Degas however, Degas: In Search of His Technique explains Degas method of using different media to fit his changing needs. Thomson's book, on the other hand, explains how Degas arrived at final compositions through drawings, tracings, and photographs.
Throughout his career, Degas was constantly experimenting and researching different mediae and was enthralled with the techniques of the old masters. Degas was not alone in his search for the techniques of the old masters. Rouart explains the situation of many artists during the nineteenth century,
It is possible that this absence of a tried and true technique did not hurt the artists but permitted them to assert their originality to a certain extent. Even though it may seem that such originality could manifest itself in style, conception and interpretation rather than in technique itself, it is obvious that their ignorance of craft brought great torment to the modern painters. (9)
Eugene Delacroix, an artist a generation before Degas, comments in his journal about the modern painters of his time lacking technique. He writes,
In our moderns, depth of meaning and sincerity burst forth, even in their mistakes. Unfortunately, their craft does not reach the height of that of their predecessors. All of these paintings will soon parish.' (10)
Degas used many different mediae during his career to include: oils, pastel, gouache, tempera, monotype, counterproof, printmaking, pencil, and essence. The last media of this long list called "peinture a l essence," was unique to Degas. Essence is a method, invented by Degas, using thinned and "de-oiled" oil paints on paper. Although similar methods in essence had been used separately by artists before Degas, he was the first to bring these elements into one medium.
The technique of painting on paper was invented long before Degas' time. Artists would thin oil paints with turpentine and paint on paper that was oiled. Degas added the technique of placing his oil paints on blotting paper to draw the oil from them. This blotting technique had also been used in the past, but for a different purpose. By de-oiling their oil paints, artists could place an opaque grisalle to glaze over without worry of cracking. Degas would employ both of these techniques to paint on paper with de-oiled paints that were further thinned with turpentine. This method of painting lets him use his brush similar to a pencil for drawing.
Many other examples of Degas techniques in the media mentioned above are explained in great detail. I found this book very inspirational to my study and it has helped me in my own search for the techniques of the old masters. Like Degas, I believe that technique is valuable to an artist's effectiveness. The only way to study technique is to study the artists and art of the past.