First the notion that man has a body distinct from his soul is to be
expunged: this I shall do by printing in the infernal method by corrosives,
which in Hell are salutary and medicinal, melting apparent surfaces away and
displaying the infinite which was hid.
Blake, The Marriage of Heaven and Hell
In the 1780s Blake began experimenting with a way of combining his poems and
his pictures through a form of colour printing. He was not the only person
to have experimented with these ideas at this time, but the
solution he reached was one of intriguing beauty and great originality.
Conventional etching depends on the design being etched into the copperplate
(intaglio). Blake, however, decided to reverse this method by etching in
relief, that is to say, he etched away the background and left the image and
text standing up in relief, as in a woodcut. To do this he used an
acid-resistant liquid and drew and wrote, composing directly onto the copperplate (with
brushes and a quill pen). When the acid-resistant liquid dried and hardened,
the plate would be exposed to acid which etched away the uncovered parts of
the copper. Because printing always reverses the design, the text had to be
written backwards, and slanted appropriately, in order to appear the right
way round when printed. Writing in this way may appear to be a daunting
prospect but, as an experienced reproductive engraver, Blake was well trained
in the skill. The plates were then inked with one or more colours and
printed under light pressure in an etching press. Not only were the raised parts
of the copper plate inked, the shallow (etched-away) areas could also be dabbed
with colour and printed simultaneously. The sheets were subsequently
hand-coloured with watercolour washes by Blake or his wife Catherine. The
colouring of Blake's early printed books, such as the Songs of Innocence
exhibited here, is characterized by the use of subdued colours and a limited colour range.
However, the late colour prints, such as plate 51 from Jerusalem displayed
nearby, were usually printed in strong, warm tones and richly hand-coloured.
The evolution in Blake's approach to illuminated printing that accompanied
this change has been described as a shift from the idea of 'print-as-page' to