The concept of print quality is elusive, since it depends on objective measurable quantities such as contrast, graininess, etc., but also on the subjective appreciation of potential observers. It is far from obvious that print quality (PQ) can be defined in terms of good or bad, so that every one will agree on this definition, and the question of its measurement, with objective and subjective measures, remains open. In this Communication, we would first like to propose a set of fundamental questions related to the definition and measurement of PQ. Specifically, we are interested in the definition of PQ in terms of quality concept and quality criteria, on the minimal dimension space of PQ, and on the functional relations that should be satisfied by the metrics of PQ. In the second part, we focus on the simpler case of print mottle and try to answer some of these questions. We show that wavelet transforms can be used to obtain a measure of PQ that correlates very well with the subjective evaluation of observers and use this measure to discuss the functional form of a metric of Print Quality.