As was usual for most of his paintings, he titled them using a color or two along with a non-art label such as "arrangement," "caprice," "harmony" and "symphony."
Examples of such works are shown below in approximate chronological order. Click on them to enlarge.
Symphony in White No 1 - Joanna Hiffernan - 1861-62
Mrs Frances Leyland - c.1871-74
Arrangement in Black No. 2 - Portrait of Mrs Louis Huth - 1873
He was beginning to feature dark backgrounds.
Arrangement in Yellow and Gray - Maud Franklin - 1876
Arrangement in Black - 1881
Nocturne in Pink and Gray, Portrait of Lady Meux - c.1881-82
Arrangement in Black, La Dame au brodequin jaune – Portrait of Lady Archibald Campbell - 1882-85
Harmony in Red Lamplight - 1886
Mother of Pearl and Silver, The Andalusian - Ethel Whibley - 1888-1900
Rose and Green, the Iris, Portrait of Miss Kinsella - 1902