Printer's ink, even though a subsidiary invention, was a completely new development. Unlike ink applied with the pen, printing ink had to be highly viscous, rather like a thick paste.
Bloy, Colin Henry
A History of Printing Ink, Balls and Rollers 1440-1850 (London: Wynkyn de Worde Society, 1967). Available locally, Drexel University. TP949.B55
Available locally, Chemical Heritage Foundation. TP949.B69 1972
Available locally, American Philosophical Society Library. 655.32 B62H
Dane, Joseph A.
“Two-Color Printing in the Fifteenth Century as Evidenced by Incunables at the Huntington Library,” Gutenberg-Jahrbuch 74 (1999) 131-145
Van Pelt Library. Z1008.G98
Scholderer, Victor
“Red Printing in Early Books,” Gutenberg-Jahrbuch 33 (1958) 105-107
Van Pelt Library. Z1008.G98
https://www.digizeitschriften.de/dms/img/?PID=GDZPPN000475769
[repr. pp. 265-67 in, Fifty Essays in Fifteenth- and Sixteenth-Century Bibliography (Amsterdam: Hertzberger, 1966) ed. Dennis E. Rhodes
Rare Book & Manuscript Library - Furness Collection. Z1005 .S374 1966]
Scholderer, Victor
“A Further Note on Red Printing in Early Books,” Gutenberg-Jahrbuch 34 (1959) 59-60
Van Pelt Library. Z1008.G98
https://www.digizeitschriften.de/dms/img/?PID=GDZPPN000476374
[repr. pp. 267-68 in, Fifty Essays in Fifteenth- and Sixteenth-Century Bibliography (Amsterdam: Hertzberger, 1966) ed. Dennis E. Rhodes
Rare Book & Manuscript Library - Furness Collection. Z1005 .S374 1966]
Smith, Margaret M.
“From Manuscript to Print: Early Design Changes,” Archiv für Geschichte des Buchwesens 59 (2005) 1-10; pp. 3-6 on red ink
Van Pelt Library. Z4 .A7
