Reciprocity failure
TextWhen shooting with extremely long or extremely short exposures on film, the reciprocity law (see above) has the potential to be violated, which would result in the failure of reciprocity. In such circumstances, the film maker may recommend that further exposure be applied to the negative in order to get the desired effect. When photos are taken digitally, there is no risk of a failure of reciprocity occurring.
Do you have a better definition? Share it in the comments.
