conventional plates-color adjust question

New to offset printing world
many years involved in flexo printing

My question is, at a press check, if the image is to rich in process magenta for a CMYK image, what would be the easiest way to make an adjustment to lighten the magenta a bit?

thanks

 

On press? ... Sheet some of the ink off the rollers, turn the duct down a little and try it again.

Off press? Adjust the curve in photoshop and make a new plate.

 

to add to what chris said about on press you'll wanna run about 100 set up sheets thru after sheeting the ink off just so it can even back out then you should be good.

 

are you using colour bars, densities..
if you are new to litho youve jumped straight in the deep end doing process cmyk work. good luck