The length of time the ductor roller is in contact with the ink fountain roller. On a printing press used in offset lithography, the fountain roller is that roller which is in direct contact with the ink fountain, or the trough containing the ink. The ductor roller alternates between contacting the fountain roller (and picking up a quantity of ink from it) and contacting an oscillator roller that is in direct contact with the rest of the inking system, terminating at the plate itself. Adjusting dwell is one of several ways of controlling how much ink ultimately flows to the plate. (See Inking System: Offset Lithography and Offset Lithography.)
'Dwell also refers to any general time interval in which two surfaces, substances, or objects are in contact with each other.