Hi skiman,
You can achieve higher image contrast when in reading mode with reading books in e-reader modes natively with the system; however, the degree of contrast (like using a dark background with white text) will depend on what's supported by the respective reading app, i.e., Nook, Kindle. 
Please feel free to reach out to us with any other questions!
 3 months, 3 weeks ago
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Lenovo Product Expert