From this You can:
menu:
NOTE: This setting is available only on the PCL emulation driver, PostScript emulation driver, or on the printer Embedded Web Server.
Gray Correction
Brightness
Automatically adjust the contrast enhancement applied to images.
Auto*
Off
Auto applies different gray values to each object on the printed page.
Off turns off gray correction.
Adjust the gray value of printed images.
Contrast
Adjust the contrast of printed images.
0*
* Factory default setting
Utilities Mode
Mode Menu
Mode Main Menu
Utilities
Hex Trace
Use the Utilities menu to troubleshoot printer problems.
1.From the menu list, use the Arrow buttons to scroll to the Utilities menu.
2.Press the Select button .
3.Press the Right Arrow button until the heading you want appears on the display, and then press the Select button .
4.Use the Arrow buttons to scroll through the available menu items.
5.When the setting you want appears on the display, press the Select button to save the setting.