To blur or double, as an impression from type; to mackle.

An undesirable printing condition where the printed image is smeared. Slur can result from insufficient blanket pressure due to improper packing (offset), slippage of a press part during the printing stroke (screen printing), mechanical problems on the press, or lack of ink tack. In offset printing, slur causes halftone dots to enlarge dramatically and affects color fidelity. Type can become blurred and difficult to read. Print control targets containing microline slur bars can be placed at the edge of a form to spot and diagnose a problem. Slur is distinguished from a similar press problem called doubling, where the image is printed again next to the correct version instead of smearing the ink.

become vague or indistinct; "The distinction between the two theories blurred"

See Ghost, Halo, Smear.

A condition caused by slippage at the moment of impression between the paper, plate or blanket.

An undesirable printing condition where the printed image is smeared. Slur can result from insufficient blanket pressure due to improper packing (offset), slippage on a press part during the printing stroke (screen printing), mechanical problems on the press, too lightweight a paper, or lack of ink tack.