Epson Aculaser CX28DN Series Reference Manual page 104

Filter
This function is used to sharpen the image or blur it for special effect.
Curves
This function is used to set the gamma of the image. In the graph, the
X-axis represents the input level, and the Y-axis represents the output
level. The selections include, 'Value Input', 'Folded Line', and 'Curved
Line'. There are three input controls available: the scroll bar, the editing
field, or by directly dragging the points of the folded or curved lines. This
function will allow you to brighten or darken the overview of the image
without changing the original resolution of the image.
The scroll bar and editing field are displayed when 'Value Input' is
selected.
82 Specify the Scan Settings