Brushfactory › Formats › .brush
What is a .brush file?
A .brush file is a single Procreate brush; a .brushset is a collection of them. Both are ordinary zip archives — rename one to .zip, open it, and everything below is visible.
What's inside one
A .brush holds one brush at the root of the zip. A .brushset holds one folder per brush plus a brushset.plist that records their order.
Brush.archiveThe settings. It is an NSKeyedArchiver property list — Apple's object-graph format — whose root object is a SilicaBrush with 51 fields. Almost every value is normalised to the 0–1 range rather than stored in pixels or percent.
Shape.png is the tip, Grain.png is the texture, and QuickLook/Thumbnail.png is the preview you see in the brush library. Inked parts are white in both Shape and Grain.
Negative numbers are meaningful here. A dynamics value in a SilicaBrush can be negative, and it is not an error — it means the response is inverted. The stock template ships dynamicsSpeedSize = -0.004. A converter that clamps to zero silently throws that behaviour away.
How to open it
On an iPad, send the file to the device and tap it — Procreate imports it straight into the brush library. There is no desktop Procreate for Windows, so a .brush cannot be opened on a PC without converting it first.
Converting .brush / .brushset
Out of Procreate: Procreate → Photoshop, Procreate → Clip Studio Paint, Procreate → Krita.
Into Procreate: Photoshop → Procreate, Clip Studio Paint → Procreate, Krita → Procreate.
What survives each trip, and what does not, is set out on the fidelity report.
Common questions
Everything on this page is taken from the reader that
parses the format in Brushfactory itself
(brushfactory/formats/procreate.py), which was built against the
applications' own source and against real files, not from a
specification document.