Brother DCP-120C Software User's Manual page 34

Custom (User adjustable from 0.35 × 0.35 in. to 8.5 × 14 in. or 8.9 × 8.9 mm to 215.9 × 355.6 mm.)
If you choose Custom as the size, the Custom Document Size dialog box appears.
Enter the Name, Width and Height for the document.
You can choose 'mm' or 'inch' as the unit for Width and Height.
Note
You can see the actual paper size you chose on the screen.
• Width: shows the width of scanning area
• Height: shows the height of scanning area
• Data Size: shows the rough data size in Bitmap format. The size will be different for other file formats
such as JPEG.
Scanning
2 - 7