Digital BW, The Print

What does this mean?
 Under Advanced BW > Color Controls: There are choices below the  vertical 
line on the right side.
 
Highlight Tonality, Max Optical Density High Point Shift > OFF
                                                                            
       ON
                                                                            
       ON  Full Page
Can anyone explain Max optical density and High Point Shift?  I never which 
to choose - off, on or  On full page.
 
I'm using PS5 on a PC with K3 ink on a 7800.
 
I'll be grateful for an answer.
                 Arlene
                                       

Arlene  Love
arlenelove3@... 
_www.arlenelove.com_ (http://www.arlenelove.com/)  
Tel: 215 923  2363


[Non-text portions of this message have been removed]

I believe enabling High Point Shift may reduce gloss differential � it will use very light grey ink to shift high point (255) to a different value (e.g., 253).