XCF (file Format)

XCF (file Format)

XCF, short for eXperimental Computing Facility, is the native image format of the GIMP image-editing program. It saves all of the data the program handles related to the image, including among others each layer, the current selection, channels, transparency, paths and guides.

The image data saved are compressed only by a simple RLE algorithm, but GIMP supports compressed files, using either gzip or bzip2. The compressed files can be opened as normal image files.

The XCF file format is backward compatible (all versions of GIMP can open earlier versions' files) and in some cases, forward compatible. For example, GIMP 2.0 can save text in text layers while GIMP 1.2 can not. Text layers saved in GIMP 2.0 will open as ordinary image layers in GIMP 1.2. However, XCF files containing layer groups, a feature introduced in GIMP 2.7, can't be opened with GIMP 2.6.

The use of XCF as a data interchange format is not recommended by the GIMP developers, since the format reflects the GIMP's internal data structures, and there may be minor format changes in future versions. The source code of GIMP itself (which is freely available) is the reference documentation of the format. Henning Makholm (see XCFTools below) has written a specification which has been adopted by the GIMP developers. In addition, a collaborative effort between the GIMP developers and Krita developers is underway to design a raster file format called OpenRaster, modelled on the OpenDocument format, for use in both applications in a future version.