Chapter 2.3 Specification of the Crystallographic Binary File (CBF/imgCIF)

Definition and exchange of crystallographic data

First Online Edition (2006)

Part 2. Concepts and specifications

  1. H. J. Bernstein1,
  2. A. P. Hammersley2

Published Online: 1 JAN 2006

DOI: 10.1107/97809553602060000729

International Tables for Crystallography

International Tables for Crystallography

How to Cite

Bernstein, H. J. and Hammersley, A. P. 2006. Specification of the Crystallographic Binary File (CBF/imgCIF). International Tables for Crystallography. G:2:2.3:37–43.

Author Information

  1. 1

    Department of Mathematics and Computer Science, Kramer Science Center, Dowling College, Idle Hour Blvd, Oakdale, NY 11769, USA

  2. 2

    ESRF/EMBL Grenoble, 6 rue Jules Horowitz, France

Publication History

  1. Published Online: 1 JAN 2006


The Crystallographic Binary File (CBF) is an electronic file supporting the efficient storage of large quantities of experimental data in a self-describing binary format. Its primary function is to handle large image data sets within laboratories and for interchange between collaborating groups. Except for embedded binary data segments, the format is derived from that of the pure-ASCII Crystallographic Information File (CIF), so that all suitable CIF data items describing the crystallographic experiment and description of any structural results may be included. Embedding of binary data fields makes use of Internet standard MIME headers to facilitate the identification and handling of separate binary components. Where file size or efficiency of processing are not important, the embedded binary data may be ASCII-encoded according to a specified protocol. The resultant file, containing only ASCII character data, is fully compatible with CIF and is known as an image-supporting crystallographic information file (imgCIF). This chapter describes in detail the structure and format of CBF and imgCIF representations, and explains how to convert from one format to the other.


  • CBF specification;
  • Crystallographic Binary File specification;
  • CBF syntax;
  • Crystallographic Binary File syntax;
  • imgCIF specification;
  • image-supporting Crystallographic Information File specification;
  • magic numbers;
  • binary data