PhotoReading is not a replacement for reading with your conscious mind, it is an expansion to your reading abilities. In order to activate a book, you should superread and dip, skitter or if that doesn't work, use Rapid Read. Some people have spontanious activation after they PhotoRead, but those examples are very rare. The purpose of PR is not accessing all of the information without looking at a word, but to be a more effective reader.
An example of a purpose for reading an autobiography book could be:
"my purpose for reading this book, the autobiography of Denzel Washtington, is that I am curious to find out more about his phenomenal life and the events that shaped him into the person he turned out to be". I don't know if that is your purpose, but it could be one. If you can't find a purpose for reading a book, you should ask yourself: "What would I want to know more of this book, so that I can apply it to my own situation(s)? And why do I want to know more about this book? How is this book going to affect me?"
Once you have a clear purpose, follow the PhotoReading system until the PhotoReading step. Let the book incubate for a sleep cycle (or a break of 20 minutes). Then try activating the material in multiple passes using the superreading and dipping techniques (or skittering), and if that doesn't help much, use the Rapid Read step.
Look for concepts and ideas presented in the book, instead of looking for words. I know I did that in the beginning, and you won't get any comprehension if you do that.
The first time you activate the material, you probably won't get too much comprehension. That's ok though, just take a small break of about 15-30 minutes, and do another activation pass. You can divide the book up into chapters if you wish, and activate each chapter at a time. Make a mindmap of each chapter, and create one mindmap of the entire book once you have finished all of the activation steps. You will notice the difference once you've played with activation a couple of times. Be patient, and have a clear purpose.