1. Check if the handedness is correct. You may change it in the App through iMark – Settings – Handedness to switch for left-handed and right-handed.
2. Make sure you are holding with the right angle (60 to 90 degrees), and the text is aligned in the middle of the Scanning Window.
3. Make sure to highlight after the Scanning Window lights on by gently pressing down the iMark, and move at a constant speed along the lines to complete the highlighting.