Some notes on scanning

basic use of scanners in IT lab - remember to use the two scanning machines for scanning only, and to do subsequent retouching on other machines

resetting resolution of scanner - default resolution is 150 dpi; 300 might be worth going to for finer (higher spatial frequency) engravings -- but watch out for filesizes.

special case: working with engravings - engravings are rather like computer printed line art in that they are printed using 1 bit per pixel (one color of ink) and the pixels tend to align themselves as vectors (given how the elbows and wrists of 19th century engravers moved). If engravings are old, the image may have degraded (with differential degradation of parts of the page). Unlike halftones, engravings are not printed with a periodic grain. To scan an engraving as a monochrome bitmap, and preserve all relevant detail of printing one would have to use a resolution so high (1200 dpi +)  that the original will be grotesquely enlarged. Dailey's solution: use low bit-per-pixel greyscale, with reasonable (300 dpi or higher) spatial frequency (see "Another case study on scanning of engravings", below for my rationale.)

Another case study on scanning of engravings.

Some references on printing techniques

Image Maps of Printmaking Techniques from The Printroom from the Spencer Museum of Art, University of Kansas. Provides a concise illustration of varying techniques -- lots of good images that you can zoom in on, too.

American Focus -- Links to sites discussing printing techniques and results; a presentation of the Albuquerque Museum.

Color Printing in the Nineteenth Century -- well-documented with illustrations and historical perspectives from an exhibition by the University of Delaware Library.

Intaglio engraving or line engraving -- nicely illustrated introduction from Web Libris.