Photoshop brush
Photoshop brush (ABR) is a file format used by Adobe Photoshop for brushes (graphics, and information about brush behavior).
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Format details
There are at least two different ABR formats, which we'll call "old format" and "new format". The first two bytes of the file are the major version number.
Old format
Known major version numbers: 1, 2
This format is documented in old versions of the Photoshop file formats specification.
New format
Known major version numbers: 6, 7
This format is not publicly documented by Adobe.
Some guesses about the format: Minor version number is at offset 2. This signature "8BIM" appears at offset 4; it and the rest of the file constitute a series of tagged blocks (the basic structure of which is publicly documented). The known block types are 'samp', 'patt', and 'desc'. See below for some information about the 'samp' block. The format of 'patt' is the same as that of 'Patt' (which is publicly documented). The 'desc' block contains a descriptor.
'samp' block
This information is based on guesswork, and may not be correct.
The 'samp' block contains a series of items.
v6.1 item:
| Type | Observed values | Contents |
|---|---|---|
| uint32 | Length of the remainder of this item, excluding padding | |
| Pascal string | ID | |
| 8 bytes | Unknown | |
| uint16 | Depth | |
| 4×int32 | Rectangle (top, left, bottom, right) | |
| uint16 | Depth | |
| byte | Compression mode | |
| bytes | Image data | |
| bytes | 0 to 3 padding bytes, to make the item size a multiple of 4 |
v6.2 item:
| Type | Observed values | Contents |
|---|---|---|
| uint32 | Length of the remainder of this item, excluding padding | |
| Pascal string | ID | |
| 2 bytes | 00 01 |
Unknown |
| 2 bytes | 00 00 |
Unknown |
| virtual memory array list | ||
| bytes | 0 to 3 padding bytes, to make the item size a multiple of 4 |
Specifications
Old format
- Photoshop File Formats Specification V6.0 Release 2
- Photoshop Brushes (ABR) Specification (from archive.org)
New format
- Adobe Photoshop File Formats Specification (Defines some data structures used in ABR format, but does not describe the format itself.)
Software
- Adobe Photoshop
- Konvertor
- XnView
- ABR2GBR - Most likely only supports old format
Sample files
- There are many websites offering Photoshop brushes for download. Some examples:
