Where to ask for graphics advice?

2 questions:

1. I sometimes receive pdf-files of handwritten pages with dark backgrounds. They drive me nuts, and I'm wondering how to get rid of the gray background. Attached is an image of what I'm talking about (or just a slice of a page). I would like to know how to change the background to white and the handwritten text to black(er)? (I have Adobe Acrobat 8 Pro, GIMP (I'm not good with it), and bunch of other graphics and pdf soft).

2. Should I ask this questions somewhere else since this board seems more oriented towards hardware, OS, security and maintenance issues? Where?

 

attachment (forgot before):