International Standards and Conformity Assessment for all electrical, electronic and related technologies
Main title

Colour Management

 

Colour Reproduction

 

Description of picture

A colour management workflow.
The computer in the middle represents the
CMM interacting with the user’s
requirements for different output needs.
Image courtesy of Scall Olswald

If you have ever taken a photograph with a digital camera and viewed your shot afterwards on the LCD screen, or scanned a document into your PC and then looked at the scan on screen, you have probably seen the effects of a lack of proper colour management. In short, the colours in the image you see on the camera's LCD or on a monitor screen may not sufficiently resemble those of the original.

 

The problem is that different devices handle colour in different ways. A monitor or LCD uses light to create colours while a printer will use inks or dyes. In addition, devices use several different systems of creating colours. A monitor might mix a hint of red, a splash of green and a pinch of blue light to produce a particular shade on a monitor while a printer might use dollops of cyan, magenta, yellow and black ink to produce the same shade. Different devices also have different colour reproduction capabilities, for example a picture on photo paper can have richer blacks and more vibrant colours than if it is printed on newsprint.

 

The environment in which something is viewed also makes a contribution. Consider going to see a movie. This is intended to be viewed in the dark, whereas a work of art in a gallery might be intended for viewing under very bright lights.

A major shift

We are deep into the shift from an analogue world to a digital one, a major change that requires some adaptation. The traditional worlds of colour reproduction, such as photography, books and magazines, are now merging with elements from the contemporary world such as the internet and digital television broadcasting. We have become accustomed to using these different systems and are becoming more and more demanding in the quality and compatibility of the different devices associated with them. This is why colour management standards have become necessary. Users would like colour management to work and be interoperable. Manufacturers know that well-designed colour management standards can enable interoperability while allowing for the differentiation necessary to drive ever-improving performance.

 

But how aware are people of what colour management involves? According to Lars Borg, principal scientist and engineering manager for core technology colour development at Adobe Systems Incorporated : "You have three levels of knowledge. There are people who know nothing about colour management, don't ever want to know about colour management and feel they should be saved from the intricacies of it. Then you have a second group who go to buy equipment and see that it has colour management on the box - they know it's a good thing but they don't know what it does or how to use it. Finally, there is an exclusive group of a few professionals who say 'Of course we should have colour management and we know how it works.'"

 

Standardization is an obvious answer to the challenges of colour management and three tiers of standards have emerged, corresponding in general terms to the three levels of understanding outlined by Borg.

 

For the handful of professionals who are at ease with colour management, the International Color Consortium (ICC)* has developed its own system of profiles to allow colour data to be reliably interpreted, and converted from one colour encoding to another, for different purposes, and to be used by different devices.

 

Description of picture

Adobe Photoshop uses IEC standards
in the development of its products.

A somewhat less sophisticated user may want some range of colour capabilities, but may not want to deal with the intricacies involved in interacting with ICC colour management. The needs of these users can be addressed by default ICC workflows, and standard colour encodings as are developed by both IEC and ISO.

 

For the user who does not want to interact with colour management at all, the default RGB colour encodings defined for multimedia systems and equipment are an ideal solution. These encodings are very broadly and successfully used in home and office applications worldwide, and on the internet.

 

With several bodies involved in the standardization of colour management, working together is imperative. Borg sees general usability as the key issue facing experts in the colour management field. He notes that: "Some people prefer a green picture and some prefer a blue picture but that is an expression of colour preference rather than colour management. TV is simple enough for the mass market to understand but we have to get the rest of colour management systems to that same level of understanding."

 

Colour management is not about setting your own colour preferences on a specific electronic device, such as on your computer or on your television set. Rather, it's a programmed colour scheme within your equipment.

 

* A body established in 1993 by eight industry vendors, including Adobe, for the purpose of creating, promoting and encouraging the standardization and evolution of an open, vendor-neutral, cross-platform colour management system architecture and components.