The quality of printed matter, which is one of several copies of the same
printed matter produced by a printing machine, is evaluated. An amount of
copies of the printed matter is selected from the total production of
this printed matter. The selected amount of these copies are evaluated
with regard to at least one error type which belongs to an amount of
different error types or with regard to at least one feature of the
error. Within the selected amount of copies, an error of a defined error
type or of a defined feature, which is detected on at least one of the
copies, is evaluated in relation to at least one error of another type or
feature detected on the same copy, or another copy of the selected
amount. The printed matter is classified as having good or bad quality
based on that evaluation. A common reading, producing image data, is
obtained by an image sensor from the selected copies. All of the errors
to be evaluated in relation to each other are detected from image data
gathered during the same common recording.