1. A system comprising: a memory to store machine readable instructions: and a processing unit to access the memory and execute the machine readable instructions, the machine readable instructions comprising: a feature set extractor to extract a feature set from each of a plurality of digital images of print samples, wherein the feature set is a filtered feature set that includes a feature set characterizing a printer that printed a given print sample of the print samples; a cluster component to determine clusters of the print samples based on the feature set of each of the plurality of scanned images of the print samples; and a printer identifier to identify the printer e print samples based on the clusters of the print samples.