In the absence of reflected ambient light, the contrast ratio of black to the dimmest non-black color on an OLED display is infinite, but that doesn't mean black-on-darkest-grey text is necessarily readable, even in a perfectly dark room.
In the absence of reflected ambient light, the contrast ratio of black to the dimmest non-black color on an OLED display is infinite, but that doesn't mean black-on-darkest-grey text is necessarily readable, even in a perfectly dark room.