Ricoh G410 - Manual (Page 68)

57
Functions
Erase Background
This function permits selection of the white side dynamic range for scanning.
When Erase Background is disabled
The dynamic range is set so that a white original (D value: 0.07) reaches maximum output.
When Erase Background is enabled
During scanning, the portion of the original that is closest to white is deemed to be white, and
the dynamic range is set so that the portion in question reaches maximum output.