I am a student with a visual impairment. I was able to get my textbooks in PDF format so that I have many more options. As a PDF I use Reader and the process to set accessibility is not too hard and normally I can get my high contrast(white text on black) no problem. The textbooks is broken up into numerous PDF, each of which contains a chapter, an appendix, an index, etc. I opened the PDF before setting to high contrast and the book appears no problem. When I set to high contrast, you have the option to choose the background color and the text color, so I go for a black background and white text. It allows me to change the background no problem, but the text will not change from black to white. Essentially this gives me an all black screen instead. I am able to highlight the text so it does not appear that it is simply one item and cannot be changed. Further, when I open up Chapter 2, it shows up fine with the black background and white text. This is very puzzling to me. When I went through and opened other chapters, some showed up properly and other were all black. Does anyone know what is going on or are there any other alternate tricks or settings to try?