Olivetti d-Color MF25 User Manual page 36

"Color Balance" parameter (CMYK color adjustment)
By mixing the four toner colors (yellow, magenta, and cyan in addition to
black) in a full-color copy, the colors of the document can be reproduced.
Changing the amount of each color of toner enables the tints in the copy to
be finely adjusted. Each color can be adjusted to any of 19 levels.
For details on the setting procedure, refer to "Adjusting the copy color quality
(Adjust Color parameters)" on page 8-36.
Adjusting the black tinge
x-34
200%
100%
0%
K
Black
Increasing the amount of black
Original
Decreasing the amount of black
d-Color MF25