If your character screen renders in color, inventory screen renders in color, hot-bar renders in color, but the main screen only renders in gray scale it means you have low blood.

See example: http://i23.photobucket.com/albums/b398/kegaro/2013-12-19_00006.jpg

Check 'Bleeding' section at http://dayz.gamepedia.com/Status_Effects for more information

If this note helps you please close your ticket.