A condition caused by slippage at the moment of impression between the substrate and plate. Slur is characterised by the smearing of the trailing edges of a printed image or by the appearance of a double image and can happen in both machine direction and across the web. However, slur is more common in the machine direction.



- Mechanical problems;

- Poor tension control;

- Slippage of the substrate through the press caused by improper support of the sheet;

- Wrong undercut used.



- Check path rollers are running freely and that sub­strate is not dragging. Oil or lubricate, replace bear­ings or drive belt. Check chuck holding roll core is inflated or secure;

- Adjust tension to the correct level, check load cells and ensure all nips are set correctly. On a gearless press check the substrate is synchronised with the press speed, do not exceed manufacturer's recom­mended maximum repeat length tolerances. Ensure dryers are balanced correctly so exhaust does not suck in film;

- Check pull collars and belts are not worn or set wrongly. Check parallelism between the rollers. Check vacuum levels,

- Ensure that both the plate and tape thicknesses are the same as the undercut on the plate cylinder.