There is no real solution to reading in the dark, and the best option for a reading lamp is the Screen Light Table Lamp app. It gives you the ability to read in the dark without losing the color of the book and other text.

Now, what you can do is just to enjoy your personal moment in a cool and relaxing environment by using the Screen Light Table Lamp app. You can easily use this app with a number of brightness settings. Also, the app has a sleep timer option, so you can use it and fall asleep while reading, without worrying about your phone's battery draining out.