1. A method of diagnosing a printer, wherein the printer is one of a particular type, comprising: performing a series of parametric tests on the printer at the time of manufacture to generate a set of baseline values for the printer; storing the baseline results; generating a set of maximum parametric test variations for the printer type such that each maximum parametric test variation is associated with a particular printer fault event; performing the series of parametric tests on the printer at a time of a suspected printer fault to generate a set of suspected fault values; calculating, for each of the parametric tests, the difference between the suspected fault value and the baseline value; wherein, if the difference for a particular parametric test is greater than the maximum parametric test variation for that particular parametric test, the particular print fault event associated with the parametric test variation may be indicated.