PIB News Update: Minister of Science and Technology, Health and Family Welfare, and Earth Sciences, Dr. Harsh Vardhan has informed that CSIR-National Physical Laboratory has developed a bi-luminescent security ink which glows in red and green colours when illuminated by two different excitation sources at 254 nano meters (nm) and 365 nm, respectively. The ink was prepared in a batch of 1kg and given to Bank Note Press (BNP), Dewas, a unit of Security Printing Minting Corporation of India Ltd. (SPMCIL), New Delhi. The ink is found comparable to the standards that are in use. The formulation can be used to check the authenticity of passports, Government documents, tamper evident labels, identity cards, etc.