Note that the iPad screen brightness can be turned down very far. Note that most reading software even includes some option to additionally turn the brightness

Note that the iPad screen brightness can be turned down very far. Note that most reading software even includes some option to additionally turn the brightness down by basically putting a grey filter of the screen. Note that most reading software (not iBooks) includes a white-on-black mode. With all that you can turn down the brightness to absurdly low levels that are not achievable with laptop software.