File Submission Specifications
PMC's mission is to create a high-quality archive of journal content, and to provide durable access to this archive both now and in the future. As technology and digital formats evolve, storage of and access to digital literature relies on resilient and long-lasting formats and practices. With this mission in mind, PMC has designed the following specifications for file submission.
Journals or selective deposit feeds must continue to meet PMC specifications and criteria on an ongoing basis. If content fails to meet the Basic PMC Production Requirements, PMC may apply the Production Data Requirements redress process.
A journal must provide PMC the full text of articles in an XML format that conforms to an acceptable journal article DTD (Document Type Definition). PMC’s preferred XML format is the NISO standard DTD for article publishing, JATS: https://jats.nlm.nih.gov/. Other DTDs may be used, but must be pre-approved for use in PMC.
Each individual article must be provided in a separate XML data file. All XML must conform to PMC's Minimum Data Criteria, and must accurately contain the content of each article.
PMC requires images to be supplied in an uncompressed high-resolution file format. Images should be of sufficient width and quality to be considered archival. Images generated at low resolution for display purposes are not acceptable. Images should be unpixellated and clearly legible when viewed at display size.
Specific details for figure, equation, and table image quality can be found on the Image Quality Specifications page.
A separate PDF which directly corresponds to the individual XML or SGML data file should be provided for each article. PDFs should not contain printer’s proof marks or other non-article objects.
If possible, PMC prefers to receive PDFs that meet the PDF/A standard for long-term preservation (https://www.iso.org/standard/38920.html). If a journal applies a Crossmark button and metadata to article PDFs, then the publisher should supply those PDFs to PMC.
PMC requires all available supplementary material to be submitted along with its article. Supplementary material files must be supplied directly to PMC, and the supplementary data identified in the article's XML.
Supplementary material cannot be externally linked from the article text as a substitute for deposit, though an exception may be made for data files that require custom software to read or use, or are very large (over 2GB; see Large files). Please refer to PMC's supplementary material policy and the PMC Tagging Guidelines for additional information.
Large files (greater than 2GB)
PMC can only accept files that are 2GB or smaller. In cases where files are larger than 2GB, or cannot otherwise be reasonably included with an article, NLM encourages journals and authors to make the data available in a public repository and include the relevant data citation(s) in the paper. Guidance on tagging data citations and data availability statements is available in the PMC Tagging Guidelines.
Naming and Packaging for Delivery
PMC requires that data be packaged in a compressed archive, such as a zip file, to be delivered to PMC's FTP site. The Naming and Delivery Specifications page describes naming and packaging content for PMC delivery in further detail.