Note that when using film intermediaries, careful calculations must be made in order to determine the effective dpi of the source material. Selection of the optimum resolution starts with a determination of what is the smallest meaningful element that must be legible in the end product. It is much more difficult to determine what the smallest meaningful element in a photograph or artwork is. In part it depends on who will use the scanned image and in what way. A non-specialist may look at a landscape photograph casually, while a geologist may need to be able to distinguish the stratigraphy of the cliff in the background.
Legibility results from a combination of resolution and bit depth.
Note that the higher the resolution, the larger the file size. Testing will be needed. Testing will be needed. Color - Printed documents such as maps and posters may be able to be captured fully at 200 dpi. Testing will be needed.