Developing a custom colour target for artwork imaging

摘要

When characterising digital camera for capturing art paintings, the standard targets are often used, resulting in unacceptable differences in reproducing some special colours, so additional time must be spent for visual editing and colour adjusting in various software applications. To avoid the need for excessive colour editing, and to improve workflow efficiency and colour accuracy, the special colour reference target for digital camera characterisation was developed, applied and tested in these research. The object of digitalisation was paintings made with gouache paint, so two custom gouache reference targets with different numbers of colour samples (named CGRT24 and CGRT96) were created for digital camera colour characterisation. The main criteria for construction of targets were defined, as the optimal studio conditions for digital image capture of art paintings. By analysing the results gained with profiles testing, it was established that the errors in colour reproduction, which appear when using the standard targets (GretagMacbeth ColorChecker and ColorChecker DC) was decreased when using the developed CGRT targets for digital camera characterisation. Also, it was found out that the larger number of colour samples on target does not guarantee the more accurate camera profile. The results show that the colorimetric properties of colour samples are more important than the number of samples and proves that there is a benefit of developing the custom target tailored to the specific need.