When a reader needs to verify the printmaking technique behind an early modern book illustration, I’m always happy to grab my favorite 10x loupe and head up to the Reading Room to have a closer look. By popular request, here are some of the things I look for, and some books and websites that can help.
Background: relief and intaglio
Before the invention of lithography in the 1790s, two basic techniques for mechanically reproducing illustrations existed: relief printing and intaglio printing. In relief printing, the lines that carry the ink stand up higher than the surrounding surface. The image is created by cutting away the parts you don’t want, inking the block, then pressing a sheet of paper onto the inked block. It takes relatively little pressure to transfer the ink to the paper, so relief prints are made using a common press, the same press used for the text of a book.
Relief blocks and moveable type use the same press, so they can be printed at the same time, making it simple to include image and text on the same page. Most early modern relief prints are woodcuts, though metal cuts were also made.
In intaglio printing, the lines that carry the ink are cut into the surrounding surface. ((“Intaglio” comes from the Italian verb intagliare, meaning “to carve” (the “g” is not voiced, same as in lasagna).)) Engraved lines are cut into the metal plate by a sharp tool. Etched lines are cut into the plate by acid eating away at metal exposed by scratching through a protective layer of varnish. The image is created by incising lines on a metal plate, forcing ink into the incised lines, wiping the surrounding surface clean, then pressing a dampened sheet of paper onto the plate under such high pressure that the paper is squeezed into the incised lines, where it picks up the ink. Because of the enormous pressure needed, intaglio plates have to be printed on a rolling press.
In other words, if you see an intaglio print on the same page as the letterpress text of a book, that page has gone through two printing presses: a common press for the text (with a gap left where the illustration should go), then a rolling press for the image.
Questions to help identify technique
Is there a plate mark? A plate mark is the impression that a metal printing plate leaves in the paper thanks to the high pressure of a rolling press. The corners are rounded (because sharp corners on the printing plate would damage the paper) and the edges often show traces of ink that wasn’t fully wiped off plate. Plate marks characterize engravings, etchings, and other types of intaglio print, though sometimes the mark is no longer visible.
In prints from the early modern period, plate marks rarely extend more than a few millimeters beyond the image area, since the expense of the copper or copper alloy plate made it important not to waste any material. This decorative initial, from the 1698 edition of Alfred the Great’s Anglo-Saxon translation of Boethius, is particularly well-printed, with the image sitting perfectly straight in the space left for it.
Do the black lines look like they were made by cutting away the white parts, or vice versa? With woodcuts, it’s often easy to imagine the image being the result of what was gouged out, particularly if you look closely at the shading.
In this close-up of a kneeling man pruning a tree, you can see that the shading on his arms and legs and on the tree trunk is made by cutting out little wedges between the short lines, then cutting a long line at right-angles to them in order to have a smooth exterior outline.
What does the cross-hatching look like? Do the intersecting black lines flow smoothly, showing that they were made from a single cut? Or are they jagged in places, showing that they were made by cutting away the white diamonds between them?
The detail on the left shows engraved cross-hatching (a close-up of the roller in the illustration of a rolling press, above) while the detail on the left [UPDATE: make that “on the right”!] is woodcut (a close-up of the underside of the top of the common press, above).
Are the lines swelling and smooth, or even-width and spidery? Engraving and etching are both intaglio techniques, but the lines usually look quite different. Engraved lines flow smoothly, and typically swell before tapering to a point, as seen in the cross-hatching detail, above. Etched lines tend to look a bit shaky, maintain the same width their entire length, and have rounded ends.
In practice, intaglio book illustrations often combine etching and engraving. In the detail above, for instance, the six or seven lines shading the lower part of the thumb have been engraved (notice the tell-tale pointy ends).
Useful resources for identifying printmaking techniques
This blog post only scratches the surface (ha!) of how to identify early modern printmaking techniques. For more information, consider the following books and websites:
Gascoigne, Bamber. How to identify prints: a complete guide to manual and mechanical processes from woodcut to inkjet. 2nd ed., rev. London: Thames & Hudson, 2004.
Griffiths, Antony. Prints and printmaking: an introduction to the history and techniques. 2nd ed. London: British Museum Press, 1996.
Ivins, William Mills, and Marjorie B. Cohn. How prints look: photographs with commentary. Rev. and expanded ed. Boston: Beacon Press, 1987.
Graphics Atlas (Image Permanence Institute) at http://www.graphicsatlas.org
Image Maps of Printmaking Techniques (Spencer Art Museum) at http://www.spencerart.ku.edu/collection/print/maps/
Have other favorite resources? Please suggest them in the comments!