1. A display device comprising a plurality of pixels, wherein in each pixel, a plurality of subframe periods are provided in one frame period, and a gray level of the pixel is expressed in accordance with a time integration level of instantaneous luminances expressed in the plurality of subframe periods, wherein when an average value of gray level data of an original image is larger than a predetermined value, a first black display is performed in the plurality of pixels in one of the plurality of subframe periods, wherein when the average value of the gray level data of the original image is smaller than the predetermined value, a second black display is performed in the plurality of pixels in the one of the plurality of subframe periods, and wherein the second black display includes a black portion and a brightness portion.