Type 190 Ballistics Longitude-Latitude Photographic Plate (BLL, photoplate) is dedicated for night photography of luminous ballistics of conventional or strategical arms.
Methods X-ray dental film and panoramic pantomogram were used to determine the location of embedded supernumerary teeth on bases of the geometrical principle of X-xay photography.
Mei's father is a famous lensman and he intended to impart the skill of the photography to his bright and intelligent daughter when Mei was in her infancy.