Reciprocity failure : in photographic emulsions occurs when exposure times fall outside a films normal range. At these times an increase in exposure is required in addition to the assessed amount. This can be achieved either by increasing intensity or time.
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.