Characterising Hard Copy Printers

In order to exchange data between colour imaging devices through the medium of a device-independent colour space, it is necessary to define the relationship between the device colour space and a CIE colour space.

For some hard copy media it is possible to define the device-CIE relationship by modelling the physical properties of the media, as in the case of the Kubelka-Munk model, although in practice the relationship is more often defined through a numerical model determined from measurement of a sample of the colours produced by the device.

This chapter provides a comprehensive overview of recent work on the characterization of hard copy devices, and summarizes some recent work completed by the author in the application of polynomial regression and in the area of four-colour devices. It includes the only fully-described example in the literature of a black generation model.

The book in which this chapter appears is a collection of recent work contributed by colour imaging researchers. The chapters are based on numerous journal articles and conference papers, and summarise work undertaken over a considerable period of time by the leading experts in each area. It is used a key reference by postgraduate courses and research and development labs throughout the world.

Green also contributed two other chapters: ‘Colorimetry and Colour Difference’ and ‘Overview of characterization methods’. The latter chapter introduces the section on characterization methods which includes chapters on each class of devices.

My research interests are in colour imaging generally, and specifically in colour management, colour difference, colour appearance, colour metrolology, device characterization, colour gamut mapping and colour image quality. Colour imaging is an extremely active area of research across the world, but there remain many outstanding problems and each advance in technology throws up new research and development opportunities.My current research projects include: metrics for quantifying the smoothness of colour transforms; development of a reference printer architecture for colour management; scalability of colour gamut mapping algorithms; colour stability of printing processes; colour tolerances across different media and different cultures; psychophysical methods for assessing image quality in large sample sets; effect of surround and background on colour appearance; and colour reproduction on chromatic substrates.I am interested in the implementation of colour transforms, and have developed the Colour Engineering Toolbox, which provides a comprehensive set of tools in the Matlab language for this purpose.At LCC we have outstanding laboratory facilities in colour measurement and colour imaging, and I and my students have been able to participate in numerous national and international research projects coordinated by bodies such as CIE and ICC. We have also worked on projects with researchers at large companies such as HP and IBM.