[3] Several woman print sellers ran successful businesses in 18th-century London—for example, Mary Darly, Susan Vivares, and Elizabeth Jackson.

Humphrey was preeminent among them and became one of the top two print sellers in London, the other one being Samuel Fores.

Notable artists she published beside Gillray included Thomas Rowlandson and James Sayers.

[5] James Gillray lodged with her for much of his working life, and she looked after him after his lapse into insanity around 1810 until his death in 1815.

In Two-Penny Whist,[6] the character shown second from the left, an ageing lady with eyeglasses and a bonnet, is widely believed to be a depiction of Humphrey.