The original gouaches have not been located, but from other examples in the same manner, in Buckingham Palace and in the Uffizi, it is plain that Jackson took certain liberties. Ricci’s rather sharp colors were considerably modified and mellowed when they weren’t changed entirely: witness the two sets in different harmonies in the British Museum. Peter A. Wick (1955) believes it most likely that Jackson did not copy specific paintings, and suggests that details from Ricci’s etchings and gouaches were combined and freely amended to create Ricci-like designs.
Having determined his color scheme Jackson cut seven to ten blocks, each designed to bear an individual color which was to combine with others when necessary to form new colors. No outline block was used. To obtain variations from light to dark in each pigment Jackson scraped down the blocks with a knife; he thus lowered the surfaces slightly and created porous textures which would introduce the white paper or the underlying color. Examination of the prints clearly shows granular textures in the light areas. Scraping to lighten impressions was a common procedure in black-and-white printmaking, and was described by both Papillon and Bewick. In addition Jackson no doubt used underlays, that is, small pieces of paper pasted in layers of diminishing size on the backs of the blocks where the color was most intense. The pressure was therefore greatest in the deepest notes and lightest in the scraped parts. The copper plate press enabled Jackson to get good register without making marks on the blocks. The paper was dampened and fastened to the chase at one end. After each impression the next inked block was slid into the chase and printed wet into wet. Problems of register were eliminated because the sheets were held in place at all times, the blocks fitting the same form. No doubt the paper was sprinkled with water on the reverse side after
each impression to eliminate shrinking and to keep it soft for printing. This method would explain Jackson’s transparent effects.
Although the Ricci prints were certainly the most ambitious and complexly planned prints of the century, the cutting is crisp and decisive and the effect fresh and unlabored. As in the Venetian set embossing is consciously applied. Most likely Jackson impressed the finished prints, specially redampened for the purpose, with one or two of the uninked blocks. Jackson interpreted Ricci’s qualities with great spirit, and in doing so he liberated the color woodcut from its old conventions. The “true”-color prints he produced in the medium preceded the Japanese, if not the Chinese.[31] In Japan, it must be remembered, simple color printing in rose and green supplanted hand coloring in about 1741, and rudimentary polychrome prints can be dated as early as 1745, but, as Binyon[32] puts it, “it was not until 1764 that the first rather tentative nishiki-ye, or complete colour-prints were produced in Yedo, and the long reign of the Primitives came to an end.”
In making his Ricci prints Jackson sought a method of color printing that would overcome the deficiencies of Jacob Christoph Le Blon’s three-color mezzotint process. Le Blon, a Frenchman born in Germany, had begun experimenting with color printing as early as 1705. His idea was to split the chromatic components of a picture into three basic hues—blue, red, and yellow—in gradations of intensity so that varying amounts of color, each on a separate copper plate, could be printed in superimposition to reconstitute the original picture. This was based upon a simplification of Newton’s seven primaries. Later, Le Blon added a fourth, black plate. Incredibly, this is the principle of modern commercial color printing, the only difference being that Le Blon did not have a camera, color filters, and the halftone screen at his disposal and had to make the separations by hand. Le Blon came to London in 1719, produced an enormous number of color prints, published his Coloritto, or the Harmony of Colouring in Painting in a very small edition about 1722 (it is undated), and shortly thereafter failed disastrously. About 1733 he returned to Paris, where he attracted a few followers. Most of his prints have disappeared, only about fifty being known at present.
The idea of full-color printing, then, was in the air, although later, in the Enquiry, Jackson took pains to state that he had not been following in the footsteps of the Frenchman, who, he claimed, had made serious mistakes.
The Curious may think that this Tentamine was taken from the celebrated Mr. le Blond; I must here take the Liberty to explain the Difference.... Numbers are convinced already, that the printing Copper-plates done with Fumo or Mezzotinto, are the most subject to wear out the soonest of any sort of Engraving on that Metal. Had this one Article been properly considered, le Blond, must have seen the impossibility of printing any Quantity from his repeated Impressions of Blue, Red, and Yellow Plates, so as to produce only Twenty of these printed Pictures to be alike. This is obvious to every one who has any Knowledge, or has seen the cleaning of Copper-plates after the Colour was laid on; the delicate finishing of the Flesh must infallibly wear out every time the Plate is cleaned, and all the tender light Shadowing of any Colour must soon become white in proportion as the Plate wears. The Nature of Impression being overlooked at first, was the principal Cause that Undertaking came to nothing, notwithstanding the immense Expence the Proprietors were at to have a few imperfect Proofs at best, since it is evident they could be no other. The new invented Method of printing in Colours by Mr. Jackson is under no Apprehension of being wore out so soon.... Whatever has been done by our English Artist, was all printed with Wood Blocks with a strong Relievo, and in Substance sufficient to draw off almost any number that may be required.
What Jackson neglected to mention was the difficulty of repeating transparent color effects with large planks of wood. Few existing impressions match each other and some prints are off register. What saved him was his fine color sense, his brilliance as a woodcutter, and his disinclination to make literal color reproductions.
The work that Jackson left behind became a part of the cultural heritage of Venice, valued on its own account as well as for its connection with the city. Zanetti[33] describes the Venetian set and Zanotto,[34] in his Guida of 1856, urges a visit to the Chiesa Abaziale della Misericordia, which evidently had on permanent exhibition a “perfectly unique collection of woodcuts in various colors by Jackson, quite unmatched.”