A documentary edition is an edition based on a single manuscript, often the supposedly best manuscript, the codex optimus, but in some cases also a manuscript of particular literary or linguistic value. In the latter case, the codex optimus will usually have been edited, so making a new documentary edition is a way of supplementing the editions of the work in question. Quite a few editions of vernacular texts are documentary since they primarily are intended for linguistic studies.
A closely related term is diplomatic edition, which is commonly used for an edition which follows a single source closely. However, while a documentary edition may regularise the orthography of the source, a diplomatic edition usually never do this (cf. Haugen 2014).
A documentary edition can also be termed monotypic, since it is based on a single source.
For a fuller discussion of the term, see editions, types of.
Reference
– Haugen, Odd Einar. 2014. “The making of an edition: Three crucial dimensions.” In Digital critical editions, edited by Daniel Apollon, Claire Bélisle and Philippe Régnier, 203–245. Urbana: University of Illinois Press.
In other languages
DE: vergleichende Edition / (Text)Ausgabe, occasionally also Dokumentationsausgabe
FR: édition documentaire
IT: edizione documentaria
OH