The Open Standards Community for Electron Microscopy (OSC-EM) is a community of scientists, developers, and users interested in standardizing and sharing electron microscopy metadata.

Producing scientific results from EM data requires more than just the raw micrographs, image stacks, or spectrograms. It also requires metadata about instrument settings, sample preparation, and processing. Rather than relying on user notes or method descriptions, OSC-EM can capture this metadata in a standard format that can then be imported by processing software or published with the dataset to enable reuse and reproducible science.

Central to this effort is the OSC-EM Schema, which defines a common format for describing microscope metadata. The schema is modular to allow for the inclusion a diverse experimental techniques and data types. OSC-EM can be used to store metadata for the full data lifecycle, from data acquisition through processing and deposition.

Metadata is collected from microscopes or added by users. Currently, importers are available for life science and material science data. Interconversion with the mmCIF format is also available for single particle cryoEM and tomography, allowing deposition in EMDB and the PDB Additional importers for other instruments and experimental techniques are anticipated in the future.

OSC-EM is an inclusive community that aims to represent the needs of diverse electron microscopy users. We are actively looking for additional contributors to add additional experimental methods, instruments, and software. If you would like to contribute, please contact Spencer Bliven (PSI) or Carlos Oscar Sanchez Sorzano (CSIC).

The following projects use OSC-EM:

• The OpenEM consortium uses OSC-EM for metadata at 8 major Swiss EM facilities. An example dataset is available using the OSC-EM schema for the scientific metadata.
• CryoEM processing framework Scipion will add support for importing and exporting OSC-EM metadata in a future version.
• The European Bioinformatics Institute (EMBL-EBI) contributes to OSC-EM through the mmCIF converter. The mmCIF files produced are compatible with the wwPDB OneDep platform for deposition into EMDB and PDB.

The OSC-EM schema is under active development as of 2024 and may undergo significant changes. A stable draft version is anticipated in mid 2025.