LinuxWhat is the GBR file format?
.GBR files are used by the image editor GIMP as native brush stamps. Files with the .gbr extension contain a raster brush bitmap plus additional parameters such as a description, brush spacing, pixel dimensions, and color-depth settings. Those parameters define settings for the brush tool, one of the many editing tools offered by GIMP. Custom brush settings are especially helpful when defining bespoke brush patterns. Default brush shapes are also stored as .gbr files distributed with GIMP. Users can create custom brushes using GIMP by designing a shape on a canvas and exporting it as a .gbr.
Technically, .gbr uses the GBR v2 binary format. It begins with a fixed 28-byte big-endian header containing the brush dimensions, bytes-per-pixel (1 for greyscale, 4 for RGBA color), and a GIMP magic identifier at byte offset 20. The raw pixel data follows a null-terminated brush name string - no compression is applied. The format is fully open and documented by the GIMP Development Team.
Each .gbr holds exactly one brush stamp. By using brush patterns saved to .gbr files, artists can quickly and effectively create digital graphics using custom effects. Brushes offer consistency, and different color schemes can be applied to them. .gbr files can also be used for creating and applying custom logos or graphic signatures in authored projects. For brushes with multiple sub-images - animated or pipe-style brushes - the related .GIH (GIMP Image Hose) format is used instead. GIMP also accepts .ABR (Adobe Photoshop brush) files for cross-application compatibility.
Security & safety
RISK: LOWGBR is a passive raster data file with no scripting or macros. It is safe to open in GIMP. Download brushes from reputable sources (GIMP Brush Database, DeviantArt brush packs); a file disguised as a .gbr brush that is actually an executable is in the realm of general download caution rather than a format-specific risk.
Format details
in a nutshell- Gerber PCB format (.gbr / .GBR) - The dominant other use of .gbr: Gerber RS-274X is the de facto standard for printed-circuit-board (PCB) layer data (copper, solder mask, silkscreen, drill etc.), developed by Gerber Systems Corp and now maintained by Ucamco. The two formats - GIMP brush and Gerber PCB - are completely unrelated; identify by context (graphics vs. PCB workflow).
- Gerber RS-274-D (obsolete predecessor) - The original Gerber 'standard' RS-274-D required separate aperture tables; superseded by RS-274X (Extended Gerber) which embeds aperture definitions in the file.
Programs that open GBR files
Windows3 apps
GIMP
Open-source Copy the .gbr to %APPDATA%\GIMP\<version>\brushes, then in GIMP open the Brushes dialog and press Shift+F5 (or Filters > Script-Fu > Console: gimp-brushes-refresh) to load it. 
XnView MP
Freemium XnView MP can open GBR v2 brushes as images for viewing/export; note the older XnView Classic also lists GBR support. 
Krita
Open-source Krita can import .gbr brush files - open Brush Settings and Import the .gbr to use it as a brush preset. 
macOS2 apps
GIMP
Open-source Copy the .gbr to ~/Library/Application Support/GIMP/<version>/brushes and refresh brushes with Shift+F5. Technical details
deep spec| File type | Binary raster brush stamp |
| Encoding | Binary |
| Byte order | Big-endian (all uint32 header fields) |
| Header size | 28 bytes (fixed) |
| Magic bytes | 47 49 4D 50 (ASCII "GIMP") at byte offset 20 in the header |
| Color modes | Greyscale (bytes-per-pixel = 1) or RGBA color (bytes-per-pixel = 4) |
| Compression | None - pixel data stored uncompressed after the header |
| Typical file size | A few KB to a few hundred KB (single uncompressed raster stamp) |
| Header fields | header_size, version, width, height, bytes-per-pixel, GIMP magic (offset 20), default spacing |
| Brush name | Null-terminated UTF-8 string immediately following the 28-byte header |
| Format version | GBR v2 (current, with GIMP magic and spacing fields); GBR v1 deprecated (lacked magic/spacing) |
| MIME type | image/x-gimp-gbr |
| Related brush types | .gih (animated/pipe brushes), .vbr (parametric brushes), .pat (fill patterns), .abr (Adobe Photoshop brushes) |
| Released | 1990s, with early versions of GIMP; GBR version 2 is the current form (specifies a 'GIMP' magic at offset 20) |
| Latest version | GBR v2 (current; GBR v1 deprecated) |
| Open standard | Yes · royalty-free |
| Specification | developer.gimp.org |
GBR conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about GBR files.
