Keylines

Lines on a mechanical or negative showing the exact size, shape, and location of photographs or other graphic elements.
Found on http://www.e-printing.co.uk/glossary.htm

Keylines

Lines on a mechanical or negative showing the exact size, shape and location of photographs or other graphic elements. Also called holding lines.
Found on http://www.tso.co.uk/solutions/publishingsolutions/printproduction/printglo
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