A while back, I had some very bad cataracts. In order to view text more easily, I somehow managed to change black text against a white background to white text against a black background in the pdf reader's settings. A side effect of this change was that color became grayscale. I would now like to return the settings to default. I've lost the article on how I made the changes. How can I get the pdf reader back to it's default settings? I've tried uninstalling and reinstalling Firefox. The settings did not change. Help!