Mary Cassatt’s “Set of Ten” (1891) prints are considered some of the most inventive in the history of modern printmaking. Using two to three metal plates, and a combination of soft ground, drypoint, and aquatint techniques, Cassatt created 25 copies of each scene in the set. Follow along with Christina Taylor, conservator of works of art on paper at the Philadelphia Museum of Art, to learn how Cassatt made her iconic color print, The Letter. 

Step 1: Drawing

Cassatt started off by drawing her composition on paper.

Step 2: Transferring the drawing

After coating a metal plate in soft ground — a sticky, wax-based substance — Cassatt placed her drawing on top of the plate. She then traced over the drawing, applying pressure to lift soft ground from the plate beneath.

Cassatt then submerged the plate in an acid bath. Wherever there was acid-resistant soft ground, the plate was protected. Everywhere with bare metal — where the tracing was done — was etched lightly into the plate.

Step 3: Drawing lines with drypoint

Cassatt used her etched plate as a guide to start her drypoint (a technique in which a sharp needle scratches directly into an uncoated metal plate). Scratching into the plate, she displaced some of the metal, creating raised burrs.

Cassatt then inked the plate, pushing ink into the scratches and burrs while wiping away excess ink from the surface. Using a roller-style press, she printed the image onto paper. She then used this inked print to transfer the drawing onto two other plates, a process called counterproofing. The rich, velvety lines of her drypoint can be seen in early proofs of The Letter. 

Step 4: Adding tone + color with aquatint

Cassatt used the counterproofed image on the plates as guides for her aquatint (a technique in which areas of tone are added to a print). In order to create a specific shape in aquatint, Cassatt applied an acid-resistant shellac to protect certain areas of the plate during etching. For example, she used this technique around the flowers in The Letter.

Once dry, she dusted rosin (dried tree sap) evenly over the plate and fused it to the plate with heat. Again, she placed the plates in an acid bath, etching the metal around the rosin and creating textured areas to hold ink.

Step 5: Inking + printing

Cassatt applied colored ink to the etched areas of her three plates. Adjacent colors that Cassatt did not want to be mixed (such as the brown of the desk and blue of the dress) were applied to different plates, and different colors were applied to the same plate using a technique called à la poupée. You can see in The Letter that Cassatt inked the blue dress on the same plate as the pink and green flowers, since some blue can be seen mixing into the flowers around the dress.

After wiping away excess ink, Cassatt printed all three plates in perfect registration onto one sheet of paper to create her final print.

To see the full process of recreating Cassatt’s The Letter, watch “Demonstrating Mary Cassatt’s Color Printmaking Techniques.”