•The optical properties of a material from a technological aspect are normally described in terms of their ability to transmit light, to exhibit color and reflect light from the surface (i.e. gloss).
•The majority of food packaging films are unpigmented, but some are colored by the addition of colorants.
•main pigments as colorants in packaging are carbon black, white titanium dioxide, red iron oxide, yellow cadmium sulfide, molybdateorange, uItramarineblue, blue ferric ammonium ferrocyanide, chrome green, and blue and green copper phthalo cyanines.
•The FDA has questioned the use of some of these colorants in packaging material in contact with food, their concern being with colorants which can migrate from the packaging into the
food.