Portland Common Data Model: Use Extension 2021-04-09 Ontology for a PCDM extension to add subclasses of PCDM File for the different roles files have in relation to the Object they are attached to. 2021/04/09 extracted text A textual representation of the Object appropriate for fulltext indexing, such as a plaintext version of a document, or OCR text. intermediate file High quality representation of the Object, appropriate for generating derivatives or other additional processing. original file The original creation format of a file. preservation file Best quality representation of the Object appropriate for long-term preservation. preservation master file Best quality representation of the Object appropriate for long-term preservation. Note: This class has been deprecated in favor of PreservationFile. true service file A medium quality representation of the Object appropriate for serving to users. Similar to a FADGI "derivative file" but can also be used for born-digital content, and is not necessarily derived from another file. thumbnail image A low resolution image representation of the Object appropriate for using as an icon. transcript A textual representation of the Object appropriate for presenting to users, such as subtitles or transcript of a video. Can be used as a substitute or complement to other files for accessibility purposes.