The unit data element originating from an electron microscope is a micrograph. Typically, a collection of micrographs are taken of the same specimen, intended to be all processed in the same way. In Bsoft, this is defined as a "project", and is tied to a specific specimen produced in a specific manner under a specific set of conditions. Changing one single parameter in the production of the specimen constitutes a new project.

There are several instances where multiple micrographs are taken of the same field. Common examples are focal series and tomographic tilt series. Within a project, there is a grouping level called a "field", which contains all micrographs from the same field (also called a "field-of-view").

In single particle analysis (SPA), small images of single particles in each micrograph are extracted for further processing. In tomography, a subfield may also be extracted and accessed at this level.

The micrograph parameter hierarchy is therefore: