.KRA File Format

Introduction

KRA is the working file of Krita, the free and open source painting program. It keeps everything needed to carry on painting: paint layers, vector layers, groups, masks, filters, blend modes and the document’s colour profile.

Krita’s source code is public, so the format can be read from it, but there is no separate full specification. Other programs that need a Krita picture usually read the flattened copy stored inside the file.

Structure

A KRA file is a zip archive. Its first entry is an uncompressed file named mimetype holding application/x-krita, so the text shows near the start of the file. The archive also holds maindoc.xml, which describes the image and its layer tree, documentinfo.xml with the title and author, a folder of layer data in Krita’s own tiled format, mergedimage.png with the flattened picture, and a small preview.png.

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