ISO 11506:2017 specifies techniques for archiving electronic data to ensure their long-term integrity, accessibility, usability, readability and reliability, in order to protect the evidential value of the data.In ISO 11506:2017, long term is considered to be a period of time lasting more than a century (see ISO 18911).Black-and-white microforms processed with liquid chemicals are used in ISO 11506:2017 because the result is always an irreversible record and because of the proven quality of microforms as a long-term preservation media.ISO 11506:2017 also specifies procedures for the parallel recording, by a single production unit, of COM and COLD output from the same data.It applies to many different types of electronic data, such as text and two-dimensional graphic data which can be represented as a black-and-white image.It is not applicable to the following:- animated images or sounds;- three-dimensional images;- images in shades of grey or in colour;- X-ray images.Neither is ISO 11506:2017 applicable to microforms created from dry thermal processes, since they offer insufficient guarantees in terms of irreversibility and longevity.