Ghosts are mysterious creatures and a topic considered to be taboo. Ghosts are also a common "language" worldwide, as evidenced by every nation having its own legends of ghosts. The word ghost ("鬼") first appeared in oracle bone script in the Shang dynasty. In Shuowen Jiezi (literally "discussing writing and explaining characters"), Xu Shen (circa 58-147 A.D.) from the Eastern Han Dynasty explained that ghosts are what people become after death. Ancient people imagined that ghosts shared similar physical forms as humans but had large and terrifying heads. The radical "厶" in the Chinese character "鬼" signifies improper, evil, or secretive things, implying that ghosts harbor evil thoughts and hide in the dark to harm others. Ghosts are dark and gloomy.
Ghosts exist in a fictional world, and their physical forms are created based on people's confusion and fear about/of death, their reluctance to die, and their unfamiliarity with the world after death. Because of such fear and unfamiliarity, ancient people had created the tradition of worshipping ghosts during mid-July of the Traditional Chinese Calendar. Said month subsequently became the Ghost Month in the East. Halloween, a western ghost festival, was originally a time when ghosts roamed the human world. To drive away evil ghosts, people wore different types of masks and walked on the streets. Such a tradition ultimately evolved into a festival where children dress up as ghosts today. The atmosphere of ghost festivals in different situations has contributed to the varying appearances of ghosts.
Because ghosts are invisible, nobody knows what they look like, and painters can paint ghosts as they please using their creativity. The subject of ghosts can be found in religions, mythology, literature, art, and even movies and animations. Some ghost stories are used to express emotions, while some are used to mock current affairs. The rich content and materials have resulted in ghosts created by painters being markedly different and interconnected with religions, mythology, and literary allusions, giving birth to wonderful ghost paintings.