Open Colour Systems Collection 2.0


What is "Open Colour Systems Collection"?

Open Colour Systems Collection (OCSC) contains more than 350 colour systems, all of which use the CIE L*a*b* colour model. You can integrate and distribute those with your software in accordance with the licence.


Why CIEL*a*b*?

While RGB/HSB/HSV or CMYK values always depend on a particular output target, L*a*b* values are target-agnostic.

Since its publication 40 years ago, CIE L*a*b* has become the de facto industrial standard for colour definitions in colour measurement and composition, and it's also being used in software. For instance, colour management works on the basis of tables or mathematical formulae, which are stored in so-called ICC profiles with L*a*b* playing the role of an "international prototype metre" for colours.


Advantages of CIE L*a*b*:

- Independent of output target, neutral colour definition
- All colours are clearly defined, no gamut limitation
- CIEL*a*b* follows human perception, not device characteristics
- Each intermediate colour can be clearly defined, hence no fixed colour values (unlike Pantone, RAL etc.)
- Mathematical colour definition; no copyrights, patents or licence fees 
- Comparisons between fixed colour systems are easy

A note regarding naming/notation: While CIE L*a*b* and L*a*b* may be the official "labels", the terms CIELAB and Lab colours are widely used and accepted.


Measuring

The colour swatches in the Open Colour Systems Collection are *not* based on digital data from any of the vendors. Instead they are the result of spectrometric measuring of physical colour swatches or fans. The measuring results have been mathematically converted to L*a*b* values. These efforts began in 2002 and are still going on. 

For the measuring procedure the following paramaters were being used (as they are a de facto standard in the colour industry):

- Light source: D65
- 10° observer as defined by CIE 1976

As a result, all colour values have been created using identical conditions, which makes them comparable.


Colour systems

The measured colour systems are being used in graphics and architecture:

- Varnish and paint colours
- Facade and wall colours
- Print colours
- Foils for indoor and outdoor advertising
- Paper
- Colours for artists

Details about the respective colour systems, their area of application, as well as contact information about the vendors are included in the SBZ files themselves.


Digital Colour Atlas

The measuring was part of the development of the software "Digitaler Farbatlas" ("Digital Colour Atlas"), which enables numerous calculations with colour values, for instance:

- Comparisons (Which colour of vendor B is the equivalent of a certain colour of vendor A?)
- Harmony calculations (Which colour harmonises with the current colour? How do I gradate the colour?)
- Colour values (RGB and CMYK for many print and screen variants)
- Colourising bitmap files
- 3D preview of colour spaces
and many more.

As of this release of OCSC, the product is available for Windows and Mac OS X as version 5.0 (see: http://www.farbatlas.com [German] and http://www.colouratlas.com/ [English]).


The GPL files included in this release are intended for use with GIMP, Inkscape, Krita and MyPaint and provide sRGB versions of the original LAB values.

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Open Colour Systems Collection 2.0
© 2015 dtp studio oldenburg
http://www.dtpstudio.de


Licence

Open Colour Systems Collection 2.0 is being released under the CC BY-ND 4.0 licence (https://creativecommons.org/licenses/by-nd/4.0/legalcode)

You are free to share, copy and redistribute the material in any medium or format for any purpose, even commercially, under the condition that you give appopriate credit and indicate if changes were made. If you remix, transform, or build upon the material, you may not distribute the modified material. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

Please read the file Licence.txt for the complete licence.


Credits

We would like to thank

- all colour vendors and their sales offices who provided us with original colour fans and swatches.
- the staff of dtp studio oldenburg who were/are involved in the difficult process of recording and measuring.
- Christoph Schäfer (Scribus Team) for his support with this release.

