Microtek ArtixScan 4500t Reference Manual page 30

To choose your scan material:
1. Choose the Scan Material command in the Preferences menu. From the
submenu that appears, select your scan material; a check will appear next to
the selected option.
2. Alternatively, you can click the Scan Material icon (beside the Scan button),
and then choose the correct scan material from the drop-down menu that
appears.
The appearance of the Scan Material icon changes, depending on whether your
scan material is reflective, positive, or negative.
Appearance of the Scan Material Status icon when
scanning reflective materials.
Appearance of the Scan Material Status icon when
scanning a positive transparency or filmstrip. Notice the
perforations on the top and bottom of the icon
(characteristic of slides) to distinguish it from the
reflective icon.
Appearance of the Scan Material Status icon when scanning
a negative transparency or filmstrip.
Scan
Material icon
Reference: The Preview Window 23