Grey pants

Rejecting the offer of some new pants, Stephen tells Mulligan, "I can't wear them if they are grey." He is rigidly upholding an outdated Victorian convention, no doubt because of the terrible guilt that he feels about his mother's death. Symbolically, his somber black clothes also make him a type of Hamlet, rejecting his world's expectations of him.

JH 2011

The 2003 Great Lakes Theater Festival production of Hamlet, with Kevin Brewer as Rosencrantz, Steve Tague as Hamlet, and Lynn Robert Berg as Guildenstern. Source: www.greatlakestheater.org.

Stephen Dedalus, played by Maurice Roëves, and Leopold Bloom, played by Milo O'Shea, in the 1967 film of Ulysses directed by Joseph Strick.
Source: www.editoreric.com.