You can change the background color of your PDFs by setting the Themes based on your needs in the different reading environments to reduce eye strain.
1. Run PDF Reader Pro iOS and click Documents ;
2. Open any PDF file that you need to read and enter the reading page;
3. Click on the right of the menu bar (for iPad users), or on the left of the annotation toolbox (for iPhone users);
4. Under Themes, you can choose from the four default modes such as Light Mode, Sepia Mode, Reseda Mode, and Dark Mode;
5. You can also swipe the color icons to left, and then tap to customize any color in your own preference;
6. (Optional) Adjust the Brightness slider to change the screen brightness in PDF Reader Pro.
Light Mode: The default one that displays the document on a bright white background.
Sepia Mode: Displays the document in a light-yellow background, so it’s easier on your eyes.
Dark Mode: Displays the document in inverse color (like it is on film negatives) in a dark environment.
Reseda Mode: Displays the document in a light-green background to protect your eyes after long-time reading.