1. The fluorescence difference of different inks was tested by combination of multiple excitation light and receiving filter.
2. Combination of reflective light source and receiving filter to test the difference of absorption and reflection of different ink in different bands of light.
3. Combination of reflective light source and receiving filter to test the penetration effect of different bands of infrared light on different ink
4. Combination of transmission light source and receiving filter to test the penetration effect of different bands of infrared light on different ink
5. The side light source illuminates the document by grazing incidence and inspects the marks of scratch and cutting.
6. Transmitting light source illuminates the document from the bottom to the top, and inspects the trace of the document being cut and repaired.
