> "Reading a book on paper by lantern light" vs "reading the same book on Kobo by frontlight" is the same mental activity. How many times brighter was the ligh

> "Reading a book on paper by lantern light" vs "reading the same book on Kobo by frontlight" is the same mental activity. How many times brighter was the light emitted from the ebook compared to plain paper? We know that not getting sleep is bad, we know that bright lights affect sleep. For this study to be convincing we'd need a number of things: 1) more than 12 people to take part. 2) Spectra controlled but the same overall lux level in the room. Both booth and ebook emitting/reflecting the same number of lumens.