Short for experimental Computing Facility (eXperimental Computing Facility) according to abbreviationfinder.org, XCF is the native image format of the GIMP image editing program. Saves all the data that the program handles in relation to the image, which includes, among others, each layer, the current selection, the channels, the transparency, the paths and the guides.
It is used to store the original retouching on an image since it allows us to continue with the edition at any time. It keeps intact all the quality and the different elements associated with file manipulation. This causes files in this format to be very large.
Founded in 1986, Experimental Computing Facility (XCF) is an undergraduate interest computing organization at the University of California, Berkeley. The description “Experimental” was given in contrast to the Open Computing Fund and the Undergraduate Computer Science Association, which support most of the campus general interest computing wishes. As such, the XCF stands as a focus for a small group of computer scientists interested solely in computer science.
Members of the organization have participated in projects such as the NNTP, GTK +, GIMP, Gnutella, and Viola. Members of the XCF were instrumental in the defense against the Morris Internet worm.
Saved image data is only compressed using a simple RLE algorithm, but GIMP supports compressed files, using gzip or bzip2. 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, backwards compatible. For example, GIMP 2.0 can save text in text layers, while GIMP 1.2 cannot. Text layers saved in GIMP 2.0 will open as ordinary image layers in GIMP 1.2. However, XCF files that contain layer groups, a feature introduced in GIMP 2.7, cannot be opened with GIMP 2.6.
The use of XCF as a data exchange format is not recommended by GIMP developers,  as the format reflects GIMP’s internal data structures, and there may be minor format changes in future versions.. The source code for the GIMP (which is freely available) is the reference documentation for the format. Henning Makholm (see XCF Tools below) has written a specification that has been adopted by the GIMP developers. Additionally, a collaborative effort between GIMP developers and Krita developers is underway to design a bitmap file format called OpenRaster, inspired by the OpenDocument format, for use in both applications in a future release.
Since version 2.8 of GIMP images are loaded and imported in XCF format. GIMP only allows saving in XCF format; other formats have been moved to the Export dialog. Software support
XCF in other programs besides GIMP
- Seashore is a GIMP-based Mac OS X native lightweight image editing program.
- CinePaint is a fork of the GIMP with support for 16 bit and 32 bit floating point channels and 16 bit integer channels. There are plans for CinePaint to move away from XCF as a file format. The XCF file format used in CinePaint has diverged from the native GIMP format, so XCF files created in GIMP cannot be opened in CinePaint, and vice versa.
Image viewers and conversion software that can read the XCF format
- DBGallery displays multilayer images that are not indexed and allows indexing, searching and other operations of the photo database.
- ImageMagick has an XCF reader module that can read single-layer images that are not indexed.
- Dogwaffle project including PD Pro, PD Particles and PD Artist imports XCF files using ImageMagick library.
- Krita imports XCF files using the GraphicsMagick library.
- Kolourpaint can read XCF files using the KDE I / O image from the plugin library, just like any other KDE program.
- Showimg can display multiple layers of non-indexed images.
- Gwenview can display multiple layers of non-indexed images.
- GImageView can display multiple layers of non-indexed images.
- Digikam can display multiple layers of non-indexed images.
- Imagine you can display a single layer of non-indexed images.
- XnView can display single-layer images that are not indexed.
- Inkscape added support for XCF export in version 0.44.
- XCFTools by Henning Makholm is a set of utilities that deform and compose XCF images. Allows extraction of individual layers, or an entire composite image, such as PNG or PNM.
- IrfanView can display multi-layered images (composite image and individual layers).
- NET can load and save multilayer images.xcf /.xcfgz /.xcfbz2 (via ImXCF.FileType plugin)
- Chasys Draw IES can load and save multilayer images.xcf / .xcfgz /.xcfbz2 (from version 3.71.02)