Photoshop brush

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File Format
Name Photoshop brush
Ontology
Extension(s) .abr

Photoshop brush (ABR) is a file format used by Adobe Photoshop for brushes (graphics, and information about brush behavior).

Contents

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
4Ă—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

New format

Software

Sample files

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