Method of restoring RGB gray scale data and apparatus for performing the same

A method of restoring RGB gray scale data for maintaining a sharpness of a screen and reducing a size of a memory is disclosed. The RGB gray scale data having M bits are truncated to generate a first RGB gray scale data having N bits, M being a positive integer and N being an integer less than M. RGB gray scale data information is generated based on a bit information of the first RGB gray scale data. A bit value of a MSB of the first RGB gray scale data is compared with a value of a dither table based on the RGB gray scale data information to generate a comparison value, when a bit value of at least one bit of the first RGB gray scale data is different from other bit values of the first RGB gray scale data. The first RGB gray scale data are compensated based on the RGB gray scale data information and the comparison value. Thus, the sharpness of a screen may be maintained and the size of the memory may be reduced.