To adjust image density, press [] or [], at the left and right of [Auto Density]. These keys increase or decrease the image density in single increments up to 7.
Selecting [Auto Density] corrects scanning density to improve resolution of paper types such as non-white paper like newspaper or transparent originals.
When scanning originals in full color, you can specify the [Auto Density] level in [Background Density of ADS (Full Color)] in [Scan Settings] under [Scanner Features]. For details, see "Scan Settings", Preparation.