xcf

XCF is the native image file format used by the GNU Image Manipulation Program (GIMP). The file extension is .xcf. XCF files are designed to preserve the complete editing state of a GIMP project, including multiple layers, layer masks, channels, paths, guides, text layers, and other metadata, enabling non-destructive editing across sessions.

Features include per-layer properties such as opacity, blend mode, and visibility, as well as support for layer groups, channel data, layer masks, and paths. The format also stores image-wide information like color profile and image size, and can accommodate text and vector-like elements created in GIMP. It supports transparency and multiple color modes (RGB, grayscale, indexed) and is primarily intended for use within GIMP.

Compatibility and usage: XCF is not a universal interchange format; many image editors do not support it directly. GIMP users typically export to more widely supported formats (such as PNG, TIFF, or JPEG) when sharing results. Some third-party tools can read XCF or convert it to other formats, but conversions may not preserve all GIMP-specific features or editing history.

History and notes: XCF has served as GIMP’s project file format since the program’s early versions. The exact binary specification is not widely standardized in a formal public document; understanding comes from the GIMP source code and community documentation. It remains the preferred working format for ongoing GIMP projects and for preserving editability within the software.