When scanning large format documents a carrier sheet should be used when:
The original is limp as or limper than a newspaper.
The original is smaller than A4 size or a document of non-standard size.
The original tears or becomes damaged easily.
The original is considerably damaged.
The original is badly creased.
When the original cannot be properly advanced to the initial position of scanning (because the target medium is not flat, or otherwise hard to load in the scanner).
Scanning transparent or translucent documents.
Scanning curled originals.
Scanning originals where pieces of paper have been attached.
Place the original in the carrier sheet with the document's surface to be scanned face up (against the transparent top sheet).
Be sure to:
When handling the carrier sheet, be very careful not to scratch or damage it.
Be sure to use document supports when the carrier sheet is used.
As a general rule, scanning speed must be lowered if the total document thickness including the carrier sheet exceeds 0.03 inches.