Blake was exceptionally close to his youngest brother, Robert, who was also set on a career in the arts and was perhaps a lodger with the Blakes. When a quarrel developed between brother and wife, Blake made Catherine apologize humbly to Robert (Gilchrist, 1.58–9). The youth fell ill in the winter of 1786–7 and died in early February. In his exhaustion after the ‘last fortnight’ of Robert's life, having tended him ‘day and night by his bedside’, Blake fell into ‘an unbroken sleep of three days' and nights' duration’ (ibid., 1.59). But his brother's spirit remained alive for Blake and grief turned to inspiration in the following year. ‘Robert stood before him in one of his visionary imaginations, and so decidedly directed him’ in how to publish his works without ‘the expense of letter-press’ (Smith in Bentley, Records, 460). Whatever its other-worldly origins, Blake's invention of relief etching also developed from his craft as an engraver. His new method was more direct, faster, and required less technical expertise than intaglio printmaking. It permitted Blake the artist to paint his images directly on a copperplate in acid-resistant varnish; Blake the poet could write his words in the same medium. The text must be executed in reverse, so that impressions would print right-way around, but this was only a slight impediment for a trained engraver. After the uncovered areas of the metal were etched away, the images stood in relief and could be inked quickly on, and printed with low pressure from, the surface. The process embodied a unity between conception and execution—a practice that became a principle of Blake's later aesthetic doctrines—rather than the divisions between invention and production embedded in eighteenth-century print technology and its class distinctions among authors and printers, artists and engravers.
Blake's first relief etching, one that includes the related technique of white-line etching, may have been The Approach of Doom, a print based on a wash drawing by Robert in his notebook, a treasured memento that Blake used for his own compositions. A combination of words and pictures soon followed: All Religions are One and There is No Natural Religion, both of 1788, are Blake's first ‘Illuminated Books’, as he called his new genre in 1793 (Blake, 693). These aphoristic tractates reject rationalist doctrines and welcome the imaginative truths of revealed religions which were, in Blake's view, one with artistic expression.
Blake produced his first illuminated book of poems, Songs of Innocence, in 1789. These brief lyrics, their illustrations, and interlinear decorations, reach beyond the genre of children's literature to express Blake's ideal of a unified sensibility incarnate in children, as in Christ. The poems may have been influenced by Moravian hymns Blake had learned from his mother. Catherine Blake helped with the presswork and hand colouring of this and other illuminated books and bound the leaves in wrappers. Although he may have exhibited a few of these singular works at Johnson's shop, Blake apparently sold his illuminated books directly to collectors rather than through booksellers. He and his wife thereby had complete control over all stages of production and distribution.
At about the same time that he developed relief etching, Blake was composing a narrative poem, Tiriel, his first extensive attempt to create mythic texts by conflating ancient Greek, British, and Hebraic motifs. The format of the Tiriel manuscript and its associated wash drawings indicate that it was intended for letterpress publication illustrated with intaglio engravings. In The Book of Thel (late 1789), Blake combined for the first time his new mode of illuminated printing with so-called ‘prophetic’ verse in long lines evocative of allegorical meanings couched in rhetoric alternately gentle and horrific.