Gelatin : natural protein used as a transparent medium to hold light sensitive silver halide crystals in suspension, binding them to the printing paper or film, yet swelling to allow entry of processing solutions.
Deoxyribonucleic Acid [DNA]
Deoxyribonucleic acid is a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. DNA and RNA are nucleic acids; alongside proteins, they compose the three major macromolecules essential for all known forms of life.