Dell COLOR PRINTER 2155CDN User Manual page 647

When the value is not 0, enter the value using the procedure in "Entering
Values."
Slow Scan
On the Chart 2 of the color registration chart, find the medium line within the
range of white area for each color pattern (Y, M, and C). If you find the medium
line, make a note of the value (-9 +9) indicated by the medium line for each
–
color.
When the value is 0 for each color, you do not need to adjust the color
registration for the slow scan.
When the value is not 0, enter the value using the procedure in "Entering
Values."
645
Maintaining Your Printer