How did the death of William Blake’s brother Robert affect his art and poetry?

The death of William Blake’s brother Robert in 1787 was a profound and traumatic event that deeply influenced both his creative process and his artistic output.1

Artistic Technique
Blake claimed that in a vision, Robert taught him the secret of "Illuminated Printing." This method involved drawing designs and poems on copper plates using a liquid impervious to acid before etching and printing them. This innovation was transformative, as it allowed Blake to function as his own compositor, printer, binder, and salesman for his published works, ranging from Songs of Innocence to Jerusalem.12

Poetry and Imagery
The experience of witnessing Robert’s spirit ascend heavenward—described as "clapping its hands for joy"—became a recurring motif in Blake’s work:1
* Vala or The Four Zoas: Blake incorporated the imagery of the spirit’s joy, writing, "Urizen rose up from his couch / On wings of tenfold joy, clapping his hands".1
* Milton: Plates 29 and 33 of this poem feature figures explicitly labeled "William" and "Robert," depicting them falling backward as a star plunges toward their feet.1