Optical properties in the visible range of two different India ink used as biological phantoms Ali Shahin, Wesam Bachir and Moustafa Sayem El-Daher Eur. Phys. J. Appl. Phys., 93 1 (2021) 10502 Published online: 06 January 2021 DOI: 10.1051/epjap/2020200234