PW,
You'll only notice the tangerine in the beginning if you put it there and notice it. Once you've put it up there, you can choose to forget about it. You mind knows why it is there. A natural response to being in a relaxed state will actually be, that your field of vision opens up all by itself.
Practice getting into the relaxed state, then go read. If your state changes notice it. Maybe stop if you feel stressed, unhappy etc. Then come back to reading, when you can be relaxed. Being relaxed means you open up the connection more than normal that between the conscious and other than conscious mind (unconscious).
Here is the real thing. If you think you should stop...stop..if you think you can carry on...carry on. The only real expert on your PhotoReading experience is you!
Happy Travels
A