1. A method of optimizing distances between each of an array of imaging devices disposed opposite a rotating drum and configured to apply an imaging output onto a recording construction carried on the drum, the devices comprising output lens assemblies through which radiation from an associated laser is focused onto the recording construction, the method comprising the steps of: a. at a first distance between the array and the recording construction, causing at least some of the devices to apply a patch on the recording construction by means of the laser radiation, the patches being substantially collinear along a first dimension; b. establishing an altered distance between the array and the recording construction; c. at the altered distance, causing at least some of the devices to apply a patch on the recording construction by means of the laser radiation, the patches being substantially collinear along the first dimension, the patches applied at the first distance and at the altered distance being substantially collinear along a second dimension distinct from the first dimension; d. repeating step (c) at least once, the patches applied at each altered distance being substantially collinear along the second dimension; e. for the patches produced by an imaging device along the second dimension, locating a patch corresponding to a highest laser-radiation energy density on the recording construction; and f. individually fixing each imaging device at a distance from the recording construction corresponding to the distance producing thereon the highest energy density for the device.