1. A method of using telecine apparatus to scan cinematographic film which comprises a plurality of individual image frames, in which method each individual image frame is scanned a plurality of times in sequence using light which is detected to generate data corresponding to the image frame, the method including the steps of: a) for each image frame carrying out in sequence, one after the other, a plurality of sub-scans, each sub-scan being in respect of a different portion of the image frame, and each sub-scanned portion adjoining another sub-scanned portion so that data corresponding to the sub-scanned portions can be combined to produce data corresponding to a complete image frame; b) in respect of data corresponding to a first sub-scanned portion of an image frame, identifying a first data set representing a region where the first sub-scanned portion adjoins a second sub-scanned portion of said image frame; c) in respect of data corresponding to said second sub-scanned portion, identifying a second data set representing a region where said second sub-scanned portion adjoins said first sub-scanned portion; d) carrying out a correlation step in respect of the first and second data sets, whereby the correlation step identifies a correlated alignment in position between the first and second sub-scanned portions; e) carrying out an adjustment step on the data corresponding to at least one of said first and second sub-scanned portions, in accordance with the results of the correlation step, so as to optimize positional alignment between the data corresponding to said first sub-scanned portion and the data corresponding to the second sub-scanned portion, whereby the adjustment step results in at least one of the first and second data sets being modified to obtain the correlated alignment in position between the first and second sub-scanned portions to produce adjusted data; f) repeating at least one the identifying, correlation and adjustment steps so as to optimize the spatial alignment of the data corresponding to all of the sub-scanned portions; and g) combining the adjusted data corresponding to the sub-scanned portions so as to produce data corresponding to the complete image frame.