ride

In letterpress printing, a ride occurs when pieces of metal type or spacing material (leads, quads, reglets) sit at different heights within the chase because they have overlapped or settled unevenly during imposition. The result is that some sorts print darker or lighter than others, or fail to print at all, because the printing surface is no longer level. This is a registration fault that spoils the print quality across the sheet.

Rides happen most often in tightly locked formes where multiple pieces of metal have been forced together. When leads of different nominal thickness are mixed, or when a sort has been dropped and wedged at an angle under adjacent type, the face of the forme becomes a topography rather than a plane. The more tightly the forme is locked, the more pressure builds up at the high spots, and the more likely it is that a ride will worsen during the print run as vibration settles the metal further.

Detection and Prevention

A compositor finds a ride by running a straightedge across the forme or by inking it and observing uneven transfer. Prevention requires careful sorting of leads by thickness, checking that all type is the correct height to paper (usually 0.918 inches for standard English type), and using proper spacing material rather than makeshift fillers. Overfitting a chase with type that has been forced to lock too tightly is a common cause.

The name comes from the verb: pieces have ridden up or over one another, breaking the flatness of the bed. It is distinct from slur, which is a sideways smear from lateral movement during impression, and from the general category of make-ready defects. A ride must be fixed by unlocking, identifying the offending pieces, and re-imposing before the forme goes back on press.