A method of controlling an image reproduction system, wherein a process duration is estimated on the basis of a measured time (D) for the processing of a number (n) of pages that have been processed already, the method comprising storing a digital table which contains a number of pre-defined job types as well as a respective correction factor (A4) for each job type; when a job is received (S1), assigning (S2) a job type to the received job; calculating (S3) a first estimate (D1) for a time needed for processing at least a specified collection of pages from the job; calculating (S4) a second estimate (D2) by multiplying the first estimate (D1) with the correction factor (A4); when said specified collection of pages has been processed, calculating a deviation of the first estimate (D1), and updating (S9) the correction factor (A4); and storing the updated correction factor.