The Venetian prints were not merely an extension of chiaroscuro, they represented a daring effort to go beyond line engraving for reproducing paintings. Justification for this attempt is given in the Essay (p. 6):
... and though those delicate Finishings, and minute Strokes, which make up great Part of the Merit of engraving on Copper, are not to be found in those cut on Wood in Chiaro Oscuro; yet there is a masterly and free Drawing, a boldness of Engraving and Relief, which pleases a true Taste more than all the little Exactness found in the Engravings on Copper Plates ... and indeed has an Effect which the best Judges very often prefer to any Prints from Engravings, done with all that Exactness, minute Strokes of the Graver, and Neatness of Work, which is sure to captivate the Minds of those whose Taste is formed upon the little Considerations of delicately handling the Tools, and not upon the Freedom, Life and Spirit of the separate Figures, and indeed the whole Composition.
A novel device, embossing, was employed to give added strength to the prints. This development had been foreshadowed by earlier prints and pages of text which showed a slight indentation where the dampened paper received the impression. Embossing had probably first been used systematically by Elisha Kirkall in 1722-24, and by Arthur Pond in his chiaroscuros, made in 1732-36 in conjunction with George Knapton, after drawings by old masters. Jackson admired Pond’s work even though it combined etched outlines with two tone blocks printed from wood.[30] Pond’s embossing was delicate and applied sparely only in certain forms, such as ruined columns, but Jackson’s sunken areas were heavier and franker, consciously intended to give an all-over effect. Since the paper could not be pressed out without weakening the embossing, it often took on the scarred and buckled look that characterizes the Venetian chiaroscuros.
The set had occupied him for 4½ years, during which he had planned, cut, and proofed 94 blocks.
No sooner was that ended, and a little Breathing required after that immense Fatigue, in the Year 1744 he attempted to print in Colours, and published six Landskips in Imitation of Painting in Acquarello.
Title page for Gajo Suetonio tranquillo, le vite de’dodici Cesari, Piacentini, Venice, 1738.
This new set, dedicated to Robert d’Arcy, British Ambassador to the Republic of Venice, was based on gouache paintings by Marco Ricci, probably done on goatskin or leather in his usual manner. For Jackson to make these color prints was a logical step, since his work had tended toward the full chromatic range even in the chiaroscuros, which “adumbrated” color. His new prints were all color—clear, sensitive, and tonally just. It is not surprising that he seized upon Ricci’s opaque watercolors. The paintings of the Venetian masters had darkened in ill-lit churches, the shadows had become murky, there were too many figures. But the Ricci paintings were small and clearly patterned, the color sparkled.