You are correct it's knowledge that you own not the ability to parrot back the text word for word that you become aware of from a book.
To know it as if you have read it you need to do manual activation. This starts witht he questions you ask of yourself. When you ask yourself mind probing question sometimes you realise that you already consciously know the answer other times you need to use the book to help you become aware of it.
You have a lot of information in your non conscious mind. It really does turn up in you life on a need to know basis. You know how to butter toast, that knowledge is not required when you cross a road or start a car. Since the conscious mind can only hold 7 (plus or minus 2) bits of information per second. The knowledge of buttering toast is not on your conscious mind because it would use up valuable resources of your conscious mind that needs to look after you personal safety, notice what is going on around you, perhap maintain a conversation you have going.
Calling up information is often automatic and can come quickly, on cue, or like trying to remember someones name, it comes up when you are relaxed and don't need to remember it anymore but want to. Therefore one cannot guarantee that when you PhotoRead your textbooks you will automatically call up the information in a test. Strenghten your body mind connection with manual activation and you can improve your chances.
Alex