Principle of shooting method of light box: install milky white, frosted bulbs, fluorescent tubes, etc. Around and at the bottom of the light box, and distribute light for shooting material evidence, so as to eliminate the shadow of the photographed object. Shooting object and characteristics: stainless steel kitchen knife, simulated crime scene, high finish, light reflection characteristics similar to specular reflection. Light distribution mode: the horizontal distance between the four vanishing lamps and the material evidence is about 25 cm, and the illumination direction forms an included angle of 45 degrees with the horizontal plane, and it shines from four directions; The projection light box illuminates from the bottom of the object to eliminate shadows. Illuminate with scattered light: shoot under uniform scattered light, and the object will not appear shadow. So when shooting outdoors, you can use cloudy days or cool places.