At the top of each catalogue entry, the techniques employed are listed as completely and precisely as possible. Whistler used pure etching or pure drypoint on many of his plates, and he combined the two for a substantial number of prints. In most cases where etching and drypoint were used together, etching predominates, and the more direct drypoint technique was employed to correct small details of anatomy (as in Reading by Lamplight  and The Music Room ) or to add or strengthen shading (as in J. Becquet, Sculptor , reproduced below).
J. Becquet, Sculptor 
On two occasions (Weary  and The Doorway ), Whistler used the roulette wheel to reinforce lines, in the former, and to create a tonal passage, in the latter. He also experimented with other intaglio methods such as open bite -- achieving tonal areas or textures by applying acid directly to the plate, and he exploited foul biting -- the accidental pits and grainy spots or patches created by faults in etching ground or accidental splashes of acid on copper. Intaglio techniques, such as roulette and open bite, are included at the top of an entry when they are present, and foul biting is discussed in the descriptive matter when it was used to particular effect or affects the image.
The Doorway 
When Whistler combined etching and drypoint, the drypoint was often added during the course of a plate's development. In other words, the earliest proofs for a plate -- and the earliest states -- are frequently in pure etching, and drypoint work is found on later states. Where more than one technique is used in succession, the different media are recorded at the top of the entry, for example 'etching (1); etching and drypoint (2 - final)', indicating that the first state of the print was in pure etching and that drypoint was added for the second through final states. Significant increases in or removal of foul biting are recorded in the state descriptions.