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Common Colour Appearance

Fogra No.: 10.059
Project manager: Dr. P. Tröster / J. Wittmann 

Duration: 1. March 2017 - 28. February 2019
Funding: Federal Ministry of Economics and Technology for the support of "Industrielle Gemeinschaftsforschung [IGF]" via the German Federa via AiF

This project is carried out in close cooperation with the working group "CIE Technical Committee TC8-16" "CIE Technical Committee TC8-16". Further information can be found on the ICC website.

What is "common colour appearance"?

When comparing different reproductions of an original image, e.g. mapped into different output printing conditions or rendered on different output devices, those images have a common appearance if an observer regards the different reproductions as "consistent", despite a possible colour difference between those images. 

2018_en_ISOGirl_CCA_Yes_No

Since such an assessment goes beyond the scope of established colour evaluation methods (such as Delta E), this project will investigate whether such a common colour appearance is consistent between different observers and therefore could theoretically be measured. Subsequently, a practical evaluation method will be developed, to enable any end user to evaluate their own images regarding their common appearance. Thus new methods for the evaluation of larger colour differences will also be examined and developed.

Overview and objectives

Does "common colour appearance" (CCA) exist?

Measuring CCA

Metric for evaluation of CCA

10.059CCA_small10.059CCA_ColourNames10.059CCA_MetricForCCA
Paired comparison experiments with test images, which have been mapped to different output gamuts using already available tools (gamut mapping algorithms), where a consistent reproduction into those different gamuts can be assumedBased on colour names and other approaches (see also previous finding in Fogra Research Report 10.057)Development of a web-based tool which allows for an easy evalution of CCA

CCA experiment

In the course of the research project, a hardproof and a softproof version of the paired comparison experiment were conducted. Two sets of reproductions of an original image were to be compaired in order to evaluate their common colour appearance. 

CCA Matlab GUI

The user interface was coded for Matlab 2017b and guides the participants through the experiment. For the hardproof version it is necessary to lay out the created proof prints according to the arrangement shown on-screen. The softproof version is conducted by running the Matlab code (2.8 GB) on a calibrated display suitable for softproof applications.



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