While working on these prints he began—

to consider on his favourite Work in Chiaro Oscuro, and by intervals examined what he had projected at Paris. He began first to make experiments with Tints, and having proved that Four Impressions could produce Ten positive Tints, besides Tratti and Lights; he resolved to try a large Piece from Rubens’s Judgment of Solomon, with an intent to prove what could be done with the Efforts of a Type Press before he launched into greater Expences with another Machine.

He wanted this press in his home, where he could experiment as he pleased without tying up workmen or equipment in Pezzana’s shop. It might have been professional delicacy that prompted him to ask Pezzana’s permission to have a private press built, or it might have been a bid for patronage from the generous and influential printer. In any event, Pezzana responded by having his carpenters build and install the press at his own expense. To avoid official registrations or craft suspicions, he had it registered as his own. The trial proofs of The Judgment of Solomon, printed from four blocks, pleased Jackson in every regard except vigor of impression. Unfortunately no edition was published, despite the dedication to Filippo Farsetti.

Finished in 1735, this woodcut was probably the first to translate a painting in a full range of tones. From the purely technical standpoint it was an incredible achievement. Jackson created a vivid approximation of a large and complex painting and at the same time produced a vigorous woodcut. From four superimposed woodblocks, with almost no linework, he was able to capture the full-blooded forms of Rubens. By keeping his means simple Jackson asserted the importance of his cutting and printing, the expressiveness of his drawing, and the fluidity of his tones. Obviously such a procedure required major decisions as to what to omit and what to stress; in other words it required interpretive abilities of a high order.

Evidently Jackson believed that his new chiaroscuro method required heavier pressure than the platen press was capable of. (On the usual wooden screw press

the size of the platen never exceeded 13 by 19 inches, because the impressions made with a larger platen would not have been strong enough; for prints larger than the platen, the bed was moved and the platen pulled down twice.) He had the press returned to Pezzana and set out to build a more suitable printing machine.

He found there were other means to be employed beside a Type Press, and having examined the Theory of his Invention put it in Practice, by erecting a Rolling Press of another Construction than what is used for printing Copper Plates.

Illustration in Biblia Sacra published by Hertz, Venice, 1740, vol. 1. Originally cut by Jackson for Albrizzi’s Istoria del Testamento Vecchio e Nuovo, Venice, 1737. Actual size. [Enlarged view.]

In Paris Jackson had suggested using a cylinder press for printing wood blocks. The gentlemen to whom the suggestion was made, Count de Caylus, Coypel, and Mariette, were sure that the enormous pressure would split the blocks. The Englishman, on the contrary, felt that the pressure, properly controlled by a chase, would hold the blocks together. Printing would be much more rapid and the exceptional vigor of the impression would suggest a hand drawing. The use of cylinder presses for chiaroscuro printing was already well known to experts. George Lallemand and Ludolph Businck, sometime between 1623 and 1640, had used not one but a series of six cylinders on three joined presses, with three printers simultaneously inking separate blocks with different tones. Impressions were then printed from each block in succession. Papillon[26] described this press, and also another with a special chase designed at an unspecified date by Nicolas Le Sueur. Jackson’s prints show a much stronger impression than those of Businck or Le Sueur. No details of his press are known, although Thomas Bewick[27] reported that Jackson as an old man had shown him a drawing of its construction.