Adobe Acrobat 7 Professional - Manual (Page 695)

Using black-point compensation
The Use Black Point Compensation option controls whether to adjust for differences in
black points when converting colors between color spaces. If this option is selected, the
full dynamic range of the source space is mapped into the full dynamic range of the
destination space. If this option is not selected, the dynamic range of the source space is
simulated in the destination space; although this mode can result in blocked or gray
shadows, it can be useful when the black point of the source space is lower than that of the
destination space.
The Use Black Point Compensation option is selected for all predefined color
management configurations. Keeping this option selected is highly recommended.