from Wired News
'Print Clock' Dates Antique Books
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Working with the principle of physical deterioration of materials, a new technique of "dating" printed materials has been developed and tested on 16th- and 17th-century printed maps and books. What is interesting is the working assumption that the printing plates - either made of wood or copper - deteriorated at a relatively constant rate even if not used, resulting in subsequent print runs with increasing "line breaks" and discrepancies. And it took a biology professor to figure that out!