gray scale
When a monochrome image is reduced in size, employing the intermediate brightness of intensity levels (gray color) will result in a better display view.
For example, if the size is reduced by half in both the vertical and horizontal directions, four dots are converted into one dot. In this case, the intensity of the reduced dot is changed to a gray color. The level of the gray color is determined by how many dots have black with the four dots before the reduction. In this example, the gray scale can be in levels of 0 to 4.
Dviout can have gray scale colors of 16 intensity levels at maximum.