tell me about copying thick media

Auto-adjustment of the scanner's light profile, stitching etc. only takes place with the insertion slot in the Normal position. With extended media thickness positions, the last performed auto-adjustment is stored and utilized. This means that you should from time to time return to the normal position, and especially when turning the scanner on, to allow it to auto-adjust.

The Normal position also gives the highest scanning speed. In the extended media thickness positions, scanning speed is automatically reduced. See:

...how do I change the insertion slot height?

Thick stiff originals will rest on top of the scanner rollers and thus raise a small distance over the glass plate, which will lead to changes in the stitching of images at points between the cameras (overlapping pixels). The stitching parameters will need to be modified in order to correct for this. You can modify stitching parameters in your application's Scanner Setup dialogs.

Scanning thick originals can give distortions when the front edge meets the exit rollers or the trailing edge leaves the entry rollers. To omit this, the leading and trailing edges are by default skipped when in one of the extended media thickness positions.

To facilitate scanning of thick originals in the extended media thickness positions it is important to insert the original center aligned and to help support the original during scanning. This should be done both at the entrance side and the exit side of the scanner. Specially designed support tables can be attached behind the scanner for those who perform a lot of thick media scanning.