A printer comprising: at least one ejector head having an array of ejectors from which drops are ejected; at least one actuator operatively connected to the at least one ejector head that ejects drops; a plurality of photosensitive devices, each photosensitive device being configured to generate an electrical signal that corresponds to an amount of light received by the photosensitive device; and a controller operatively connect to the at least one ejector head that ejects drops, the at least one actuator, the light source, and the plurality of photosensitive devices, characterized in that the printer further comprises a light source and a louver positioned adjacent the light source, the light source comprising a light pipe having a first end and a second end and a plurality of openings along the light pipe between the first end and the second end, and a light emitting diode that directs light into one end of the light pipe to enable light to be emitted from the openings in the light pipe and pass through the louver; in that the ejectors are configured to eject clear drops, the at least one actuator being operatively coupled to the at least one ejector head that ejects clear drops; and in that the controller is configured to operate the at least one ejector head that ejects clear drops to print a test pattern having dashes formed with clear material drops on a substrate as the substrate moves in a process direction past the at least one ejector head that ejects the clear drops, to operate the light source to direct light through the louver onto the test pattern of dashes on the substrate, to receive from the photosensitive devices the generated electrical signals that correspond to the amount of light received by the photosensitive devices, to identify positions of the dashes in the test pattern with reference to the generated electrical signals received from the photosensitive devices, identify with reference to the identified positions at least one misalignment distance for the at least one ejector head that ejects the clear drops, and operate the at least one actuator with reference to the identified at least one misalignment distance to adjust alignment in the cross-process direction of the at least one ejector head that ejects clear drops. at least one ejector head having an array of ejectors from which drops are ejected; at least one actuator operatively connected to the at least one ejector head that ejects drops; a plurality of photosensitive devices, each photosensitive device being configured to generate an electrical signal that corresponds to an amount of light received by the photosensitive device; and a controller operatively connect to the at least one ejector head that ejects drops, the at least one actuator, the light source, and the plurality of photosensitive devices, characterized in that the printer further comprises a light source and a louver positioned adjacent the light source, the light source comprising a light pipe having a first end and a second end and a plurality of openings along the light pipe between the first end and the second end, and a light emitting diode that directs light into one end of the light pipe to enable light to be emitted from the openings in the light pipe and pass through the louver; in that the ejectors are configured to eject clear drops, the at least one actuator being operatively coupled to the at least one ejector head that ejects clear drops; and in that the controller is configured to operate the at least one ejector head that ejects clear drops to print a test pattern having dashes formed with clear material drops on a substrate as the substrate moves in a process direction past the at least one ejector head that ejects the clear drops, to operate the light source to direct light through the louver onto the test pattern of dashes on the substrate, to receive from the photosensitive devices the generated electrical signals that correspond to the amount of light received by the photosensitive devices, to identify positions of the dashes in the test pattern with reference to the generated electrical signals received from the photosensitive devices, identify with reference to the identified positions at least one misalignment distance for the at least one ejector head that ejects the clear drops, and operate the at least one actuator with reference to the identified at least one misalignment distance to adjust alignment in the cross-process direction of the at least one ejector head that ejects clear drops.