The Printing Process
The relief-etched plates are inked using a leather-covered dauber, as Blake did (rollers were not invented until near the end of his life). With a dauber, the ink is slowly built up in mist-thin layers on the delicate relief surfaces. A letterpress printer’s “ball” is too large and cumbersome to apply ink with the delicacy of touch that is needed, and the “dollies” with heads the size of a marble or smaller, used in applying coloured inks à la poupée in intaglio colour printing, are too small. As Blake must have found, a dauber approximately 60 mm. in diameter is best, with the face partly flattened and firm, smooth leather stretched across, then wrapped and firmly tied around the base of the handle. With such a dauber, and with time, patience and skill, thin layers of ink are applied by ever-so-lightly touching the relief plateaus, dozens and dozens of times; the face of the dauber being just large enough to spread across most of the etched shallows, little more than one-tenth of a millimetre below.
Once the plates have been inked, any of the shallows that have been inadvertently touched by the dauber must be carefully wiped, using a fine clean rag firmly held over the end of a sharp stick or other pointed instrument. Plates of the Songs can take to up to 30 minutes or more to ink and wipe, while the plates of America and Europe can take up two hours. This may help to explain the care and especially the time that Blake needed to ink and wipe his relief-etched plates, as described by John Jackson and W. A. Chatto in A Treatise on Wood Engraving, Historical and Practical (1839).
Following Blake's practice, in some cases plate edges and other discrete relief surfaces are also wiped. In spite of these efforts some instances of spattering, tiny driblets of ink and traces of wiping may be found, an inevitable result of inking and wiping the plates as Blake did and a characteristic of many of his printed impressions. Printing itself is carried out in Edinburgh on an early nineteenth-century Hughes & Kimber star-wheel rolling press dating from the 1830s.
Because Blake etched his copper plates of text and design in relief, leaving the printing surface standing proud, rather than etching them conventionally by biting into and below the surface of the plate, he was able to print from these raised surfaces using very little pressure. This was done in order subsequently to be able to print on the verso of the sheet, with the result that when the sheets were bound together printed impressions faced one another as in a conventional book. Using very little pressure also made it possible to print a second impression from the same inked plate by slightly increasing the pressure. This was done by adding sheets of paper or a very thin wool blanket before passing the plate and new sheet of paper to be printed between the rollers. This resulted in a printed impression where the ink was thinner, thus transforming the colour, for example from a dense blue-black to a thin beryl green, depending upon the pigments used to mix the ink.
This practice can be taken a stage further, by printing a second, third and even a fourth impression from the same inked plate, with the result that not only is the colour of ink very much thinner with each subsequent impression, but due to the increase in pressure upon the soft, dampened and blotted paper, the embossing that is created increasingly reveals the contours of the relief-etched copper plate itself. Although this was not Blake’s practice, the result can be extremely attractive as well as instructive, giving to the impression a subtle three-dimensional or sculpted quality.
As each plate has been carefully inked by hand it is impossible to duplicate the same layering and grainy texture of the ink when the plate is again prepared for printing, with the result that not only is each set of impressions different, but each impression within a set, being printed lighter and thinner than the one before, is also unique. Thus, like Blake’s originals, no two impressions of the same image are identical, even when printed using the same mix of ink.