Solution
Adjust the levels of yellow, magenta, cyan, or black.

<->
Makes the selected color lighter.

<+>
Makes the selected color darker.

<Fine Adjust>
Fine tune the colors by adjusting the levels of the 3 density areas for each color.

Example: If you want to make a copy with colors that more closely match the original

Example: If you want to make a copy with brighter colors than the original