When you understand the information in the book consciously to the same level or better than what you get with traditional reading; you have activated the book.
It will feel pretty much like traditional reding as a beginner you would be able to get through a book in 1/3rd the time it takes you to read abook with your traditional skills. So if the book would have taken you 12 hours you would probably spend about 4 hours getting to the same or better understanding using PhotoReading. As a beginner.
The more you use it the easier it gets to get your reading done even faster.
Alex