OpenRaster is a

file format A file format is a Computer standard, standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary format, pr ...

proposed for the common exchange of layered images between

raster graphics upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...

editors. It is meant as a replacement for later versions of the Adobe PSD format. OpenRaster is still in development and so far is supported by a few programs. The default

file extension A filename extension, file name extension or file extension is a suffix to the name of a computer file (e.g., .txt, .docx, .md). The extension indicates a characteristic of the file contents or its intended use. A filename extension is typically ...

for OpenRaster files is ".ora".

Background

The

Adobe Photoshop Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc. for Windows and macOS. It was originally created in 1988 by Thomas and John Knoll. Since then, the software has become the industry standard not only in ras ...

PSD file format was widely used as a cross-application file format for layered images. Adobe allowed this by releasing the format's specifications publicly. In 2006 Adobe changed this license to only grant access to and use of the specifications and documentation "for the purposes of internally developing Developer Programs ''in connection with'' Adobe Software products and incorporating portions or all of the Sample Code into Developer Programs." In response to these restrictions, the OpenRaster format was proposed by

KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-known products include the ...

and

Krita Krita ( ) is a free and open-source raster graphics editor designed primarily for digital art and 2D animation. The software runs on Windows, macOS, Linux, Android, and ChromeOS, and features an OpenGL-accelerated canvas, colour management su ...

developers Boudewijn Rempt and Cyrille Berger at the first Libre Graphics Meeting at

Lyon, France Lyon,, ; Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the third-largest city and second-largest metropolitan area of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of t ...

in the spring of 2006 and is drawn from the Open Document Format.

Requirements

Following features should be present:

General

* full freely available documentation * OpenDocument type of file format (archive with multiple files inside) * extensible, but private undocumented extensions should be excluded, any extension should be added to the spec and documentation of the file format * applications are not expected to support all features of the file format, but when manipulating the file they should not lose any information they cannot handle

Metadata

* storage of metadata using tags * possibility of storing metadata tags per layer * storage of

Exif Exchangeable image file format (officially Exif, according to JEIDA/JEITA/CIPA specifications) is a standard that specifies formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other syste ...

tags * all text data in

Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...

(

UTF-8 UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''. UTF-8 is capable of ...

UTF-16 UTF-16 (16-bit Unicode Transformation Format) is a character encoding capable of encoding all 1,112,064 valid code points of Unicode (in fact this number of code points is dictated by the design of UTF-16). The encoding is variable-length, as cod ...

)

Layers

* storage of multiple layers * storage of each layer's coordinates * storage of blending (compositing) options for each layer * storage of adjustment layers * storage of layer effects * groups of layers * color information – profile, colorspace

Other

See * storage of paths, clipping paths and text on path * selections and masks * embedding documents within OpenDocument frameworks * support undo, history of commands and actions (like PSD)

Proposals and extensions

* palette * embedded fonts (proposal to extension) * multiple pages * animation support using multiple pages and a timer (like PSD)

Challenges

According to the draft specification (as of October 2010), a major challenge for a cross-application format is that because not all of the features are available in all the programs, an image won't be displayed the same way in different applications, especially for adjustment/filters layers. A likely work-around is the optional storage of a redundant extra layer containing the fully rendered pixel data as seen after all image processing, or possibly a lower-resolution snapshot of it suitable for previewing and thumbnailing. Different implementations levels might be defined, like, tiny, simple, small, normal, full and custom.

Application support

OpenRaster has limited support in a few graphics programs and among these its cross-application use is not seamless.

References

External links

Specification website

Git repository
* *
Integration of GIMP OpenRaster into mainline
{{DEFAULTSORT:Openraster Graphics file formats Graphics standards Open formats Freedesktop.org