<p>Among other things, for jetting fluid droplets on a substrate during relative motion of an apparatus and the substrate along a process direction, a first and second jetting assemblies at least partially overlap in a direction perpendicular to the process direction so that some jets in the first jetting assembly align with some jets in the second jetting assembly along the process direction to form one or more pairs of aligned jets. A mechanism enables, in at least one pair of the aligned jets, one jet to jet a first fluid drop that has a size smaller than a size of a fluid drop the jet would otherwise be required to jet to form a desired pixel and the other jet to jet a second fluid drop that has a size sufficient to form the desired pixel in combination with the first fluid drop.</p>
