Understanding Color Management

By Abhay Sharma

An accessible but technically rigorous guide to color management for all users in all market segments

Understanding Color Management, 2nd Edition explains the basics of color science as needed to understand color profiling software, color measuring instruments, and software applications, such as Adobe Photoshop and proofing RIPs. It also serves as a practical guide to International Color Consortium (ICC) profiles describing procedures for managing color with digital cameras, LCD displays, inkjet proofers, digital presses and web browsers and tablets. Updates since the first edition include new chapters on iPads, tablets and smartphones; home-cinema projection systems, as well as, with the industrial user in mind, new additional chapters on large-format inkjet for signage and banner printing, flexography, xerography and spot color workflows.

Key features:

• Managing color in digital cameras with Camera Raw and DNG.
• Step-by-step approach to using color management in Adobe Photoshop CC.
• M0, M1, M2 instrument measurement modes explained.
• Testing of low cost, iPhone color measuring instruments.
• Updated to include iccMAX (Version 5.0) ICC profiles.
• G7 calibration explained with practical examples.
• Conventional printing conditions described - SNAP, GRACoL, SWOP, Fogra, CRPC.
• New sections on Pantone EXTENDED GAMUT Guide.
• Introduction to XML for color management applications.

Understanding Color Management, 2nd Edition is a valuable resource for digital photographers, keen amateurs and end-users, graphic designers and artists, web masters, production and prepress operators and supervisors, color scientists and researchers, color consultants, and manufacturers. It is a must-have course text for college and university students of graphics arts, graphic communications, digital photography, print media, and imaging arts and sciences.

The Society for Imaging Science and Technology (imaging.org) is an international professional society whose mission is to keep members and others aware of the latest scientific and technological developments in the greater field of imaging. A major objective of the Wiley-IS&T series is to advance this goal at the professional level. The broad scope of the series focuses on imaging in all its aspects, with particular emphasis on digital printing, electronic imaging, image assessment and reproduction, image archiving and preservation, color science, pre-press technologies, and hybrid imaging systems.

• Language: English
• Publisher: Wiley
• Release date: Jul 2, 2018
• ISBN: 9781119223689

Book preview

Foreword to 2nd Edition

The first edition of Understanding Color Management established an accessible and practical introduction to the topic. Since the first edition was published much has changed in the color reproduction landscape. Many aspects have evolved – the technology used by industry, the expectations of customers, the scientific and technical understanding of users, and also the color management architecture and the ICC profile format. Users now have a more detailed understanding of the process. International standards – developed by ISO TC 130 Graphic Technology – have aided the industry to establish and maintain good practice. Workflow procedures, based largely on flavors of the PDF/X file format, have become more sophisticated and more reliable in delivering user expectations. Software applications used in color management have changed significantly, both the established workhorses and the specialist apps and tools. Research published in the main scientific and technical conferences and journals continues to advance our knowledge of the goals and requirements of color management. Color management could be said to have developed from a niche area to a stable and predictable part of the landscape. Yet, as old problems have been solved, new problems have emerged and we are a long way from making color completely seamless between devices and documents, as the ICC aims to do.

The new edition keeps pace with these changes, and those familiar with the first edition will find a wealth of new material. The color science material has been updated, and the section on measurement instruments is substantially expanded to include material on topics such as repeatability and calibration and an explanation of the measurement modes standardized in ISO 13655. The ICC profile format is described in detail, with each of the main tag elements explained. The advantages of working with the v4 format, first introduced in 2001, are discussed and the latest ICC technology – iccMAX – is described.

Perhaps the core of the book, and the content that will be of most direct interest to readers, is a thorough description of practical color management for each of the main types of color device – cameras, displays and printers. The key topics that have been discussed by the industry for the last decade or so are reviewed and detailed context provided, and the reader is also shown how to make color management work and achieve good quality consistent reproduction.

The strength of this edition is its unique combination of accessible yet thorough description of the context for graphic arts color management, and practical guidelines on how to implement it. As a former Working Group chair in ICC, and a current representative of Ryerson University within ICC, Dr Sharma is in a good position to appreciate the complexities of the color management and its use today. He has done an excellent job of conveying the essentials to the reader.

Dr Phil Green

Norwegian University of Science and Technology, Gjøvik, Norway

ICC Technical Secretary

2017

Foreword to 1st Edition

Color management allows users to control and adjust color when images are reproduced on different devices and media. Thus, its importance grows in many industries. The explosion in the volume of color reproduction, and, more importantly, the number of people actually reproducing color images in a variety of media, is one, but not the only, reason for its importance.

The increasing demand to simplify color-reproduction processes will certainly make those processes more available, with minimal training, to those who need them. It will also increase productivity and automation in industries with color reproduction experience, such as printing and publishing. Traditional methods of color reproduction, which required some degree of skill to achieve high quality, have not been completely replaced – and probably never will be. However, relatively unskilled users can significantly improve the quality of reproduction by applying color management. Likewise, the productivity of skilled users can be significantly enhanced.

Unfortunately, color management is not a trivial subject to understand. Color management is usually based on profiles that conform to the internationally accepted ICC profile specification. Therefore, it relies on fairly advanced color science and imaging concepts. Furthermore, it depends on understanding how to control the various devices involved in color reproduction. This makes it difficult for an unskilled person who wishes to understand how color management works (and what to do if it seems to go wrong) to easily find the necessary information. Various papers can be found on the topic (such as on the ICC web site), but such papers either superficially cover the topic, or only cover a specific aspect.

For those without the color science and imaging skills, more is required if they want to understand the subject enough to decide what is needed in order to improve their color-reproduction quality and consistency.

This book presents a fairly complex subject in a way understandable to those looking for a sound introduction to the subject. It should appeal to students and those working casually or professionally in color reproduction. The introduction to the science of color reproduction is not overly complex, and the discussion on its practice is practical. Useful hints on resolving problems are included. As such, the book will be valuable to all new users and to those who wish to extend their knowledge by investigating the theory of color science and imaging in depth. Having spent over thirty years in this work, I consider color reproduction fascinating and recommend it as an enjoyable career. This book will provide an excellent first step along that path.

Tony Johnson

London College of Printing, London, England

ICC Technical Secretary

2004

Preface

There has been a huge increase in the use of color and in the number and range of devices used to produce color. There is now widespread use of digital cameras, flatpanel displays, inkjet printers, and Photoshop-type image editing software. Smartphones are able to capture high-resolution images. In commercial printing, a number of changes have occurred; instead of using a traditional proofer, such as a Kodak Approval, pages may now be proofed on an inkjet printer or may even be proofed on a monitor, with no hardcopy.

The exponential growth of affordable and good quality color imaging devices means that color imaging is now within reach of the average user, indeed we may say that color has been democratized. We are now all responsible for our own color management which creates the need for some type of user-friendly, non-proprietary, framework for color control. A unified approach, supported by all vendors, is provided by the International Color Consortium (ICC). The ICC organization is color management’s governing body. This book is all about ICC color management.

Color management is a way of controlling color in digital imaging using software, hardware, and systematic procedures. Despite being around for a number of years, color management is confusing to many users. An air of mystery surrounds this topic; many of us are not sure what color settings to use and what all the different color management terms mean. We waste a lot of time and materials trying to get the color right. Color is often one of the most frustrating and annoying aspects of digital imaging.

The aim of Understanding Color Management is to present simply, but comprehensively, an introduction to color management, so as to promote the understanding and correct use of this technology. This book provides a well illustrated, definitive source of information for all those looking to make and use profiles for digital cameras and monitors, and to understand color management for printing and proofing. The text provides sufficient technical and theoretical explanations to enable you to understand the principles of color and create successful color management workflows.

Color management has a number of time and cost-saving benefits. This textbook explains the principles and practical aspects of this indispensable technology. Once you understand how color management works, you cannot fail to be impressed – and you will not go back to the old way of working!

The Time is Right for Color Management

Color management has had a checkered history, as shown in Figure 1. At trade shows in the early 2000s, every vendor was flaunting a color management solution, at that time the technology was not ready for prime-time and there were many "inflated expectations".

Figure 1 Color management evolution can be tracked using the Gartner Hype Cycle for technology innovation.

In terms of the Gartner Hype Cycle, Figure 1, early proof-of-concept stories and media interest triggered significant publicity. Often no usable products existed and commercial viability was unproven. In the early days it was not clear how color management should be used. The problems and their solutions were not well defined. The technology was in its infancy and vendors, equipment manufacturers, and users were experimenting with different approaches and configurations. Many early products had interfaces that were complicated and non-intuitive. Because of this, the early process was complicated and the results were often poor and unpredictable.

Following the period of inflated expectations, there followed a "trough of disillusionment". This was a very dark time for color management. Color management products and processes got a bad name, and there was a general feeling that color management did not work and was too complicated for general use.

During the period referred to as the "slope of enlightenment" users realized that for color management to work there is the need to establish some standard operating procedures, to measure and monitor, and to install measuring equipment and tracking software. There is also the need to educate and train the workforce. Slowly, color management regained its status.

Following a reality-check, today’s color management has reached a stable "plateau of productivity". There are now realistic expectations for color management; there is a clear understanding of what color management can and cannot do. Color management cannot achieve perfection, but it can get us very close quickly and consistently. Note that the level of the plateau of productivity (that represents the current state of the industry) is much lower than the initial high peak of over-inflated expectations. We observe that the level of the current plateau is lower, but is realistic and achievable.

The plateau is indicative of the current generation of color management products that are truly market-ready solutions. Developments and improvements are still being made, but we have reached a stage where color management provides a stable, credible solution. Color management systems and software have been evolving, growing into new areas such as spectral color processing or expanded gamut printing, however, the fundamental framework remains unchanged. We can say that recent changes in color management have been evolutionary and not revolutionary, as we move along the plateau.

Today we have an enormous improvement in software quality and usability, cheaper and better instruments, better compatibility between software and hardware, and better integration across the whole prepress-imaging industry. The technology has matured, users are better informed, software is affordable, and the results are much, much better. There has never been a better time to get into color management and, as a result, today we see a steady growth in the adoption of color-managed solutions by advertising agencies, prepress houses, photographers, editors, print shops, and printers.

Complicated systems, variable results and over-inflated expectations severely hampered the early adoption of color management, however, the technology is now ready, are you?

Challenges for Color Management

Despite the progress made in color management technology, there remain some challenges facing today’s user.

A reason that we have to work harder at color management than at other modern technologies stems from the fact that color management is not the primary business of many supplier companies and is, therefore, not high on their priority list. Different companies are involved in digital cameras, printers and proofers, there are major management information systems and workflow systems, and there are large printing press installations. Often these vendors do not allocate resources to color management design and implementation as this area is often seen as an incidental, ancillary part of the operation. Likewise, on the customer-side, even after making a large equipment purchase, customers will not invest a little more for color management. So, despite the obvious return on investment, both vendors and customers tend to ignore color management.

There has been a shakeout in the industry, some companies have folded, others have been acquired by larger organizations, and some have diversified into other areas. This means that many of the current color management solutions contain mixed, legacy code. An infamous American thanksgiving favorite is called tur-duck-en, a dish consisting of a deboned chicken stuffed into a deboned duck, further stuffed into a turkey. All of the major color management solutions on the market today are tur-duck-en solutions, which sometimes creates a poor user experience.

Due to amalgamation in the industry, it is very common for a vendor to offer color management as a suite of different products. Instead of offering a single color management product, companies offer a number of separate products under a single umbrella. Typically, the output of one system forms the input to the next. This lack of a coherent, purpose-built solution leads to confusion for the end user and is even confusing to company representatives who advise and sell these bundled product offerings.

Poor software design and a non-intuitive user interface continues to plague color management. The ICC specification, for example, describes a color conversion process known as a rendering intent. The official name for one of the rendering intents is relative colorimetric, but a major vendor offers a drop-down menu for this rendering intent called – Full (Output GCR). How is the user supposed to guess relative colorimetric from Full (Output GCR)? In another example, a leading color imaging company has a dialog labelled CIE Illuminant D50K. An important distinction, explained in this text, is that Illuminant D50 and 5000K are two separate specifications, there is no such thing as an Illuminant D50K!

These examples demonstrate that color management software is usually very confusing to work with. Good software design and an elegant user interface are not part of today’s color management solutions and applications. Today it is incumbent on the user to know what it is they are trying to achieve and how they want to achieve it, the user must seek to achieve their goals despite color management software interfaces.

A perennial challenge for color management is that it is a solution trying to satisfy two very different audiences – the consumer who wants automatic color control and the commercial user who wants to tweak and adjust and control every aspect of the imaging process. Using an automobile analogy, the general user would like a car with automatic transmission with just two pedals, for accelerator and brake. Commercial/professional users prefer a car with manual transmission, with the ability to accelerate through the lower gears, monitor the rev counter, and use the engine for braking.

At the car dealership, you can choose between cars with automatic or manual transmission, in color management there is only one solution – one size fits all. This means that color management is often too complicated for the general user, yet too dumbed down for the commercial user. A continuous challenge in color management has been in keeping both camps happy, while sometimes it seems that solutions fall between two stools and both parties are dissatisfied.

A fundamental challenge in color management is that the underlying color science of the process is imperfect. Color is perceived by the eye-brain visual system, and our response to color is based on a number of factors, including such diverse things as the room lighting, what is in the scene, and the mood or age of the observer. Color is thus a very complex phenomenon and there are many nuances in the way that humans