CM - Why? and Why me?

Anyone who has ever scanned an image or taken a digital photo, looked at it on a computer screen and then printed it in colour can easily explain understand why we need Colour Management in digital imaging.

Input, display and output devices do not "see" colour the same way. Monitors and scanners use RGB colour (with red green and blue combining to form a range of available colours). For the most part, printers use CMYK process inks to produce colour. Whether on a printing press or on the desktop.

The range (or gamut) of colours that can be created using red green and blue light is different from the range of colours which can be created when using process inks to print on paper. So when a user converts images from the RGB ColourSpace/profile to the CMYK ColourSpace/profile of a printer or press, the colours are unlikely to match.

In 1995, the introduction of Apple's Colorsync 2.0 technology was a milestone in Colour Management on the Mac. This system level SW enables the use of device profiles which characterize devices by measuring the colour changes which those individual devices make to images during the scanning or capture, printing and viewing processes. Microsoft eventually introduced similar system level colour in Windows 2000.

When devices are characterized by building ICC profiles of them, Colorsync and other profile compatible system level softwares can help graphics applications to compensate for the changes made when colour is handled by those devices.

Before the introduction of Colorsync 2, device profiles had been used only in proprietary systems [e.g. Quark X's Eficolour), but from now on the profiles would be made to ICC [International Colour Consortium) specifications and so can be utilized across an ever expanding range of applications throughout the workflow.

The release of Photoshop 5 introduced a new idea to the mainstream of digital imaging, the concept of the "Device Independent" storage space or "Workspace" - since Photoshop 6 called a "WorkingSpace", further expanding the capabilities of colour management.

Device Independent WorkingSpaces, as we now call them, were invented to contain image data in a linearized and universally recognized form, so that image files could be passed between devices and between users - whose computers simply have be set up to read an embedded profile, often called a tag. This embedded tag provides sufficient information about a file’s provenance to allow proper display and processing of the image whether done by the creator or another user later in the chain of the workflow.

Plainly a standard for monitor calibration and profiling becomes essential at this stage in the development of Colour Matching procedures, because we need to know that what we see on our own screen will be very similar - if not identical - to the image seen by another compliant user. Be she originator, manipulator, colour corrector or the printer who will make the films and plates.

Cross device Colour Matching is further enabled by the inclusion of different Rendering Intents in the standard. During a conversion from input device to WorkingSpace, WorkingSpace to calibrated and profiled screen or WorkingSpace to printer, the way in which the colours are translated from one to the other is controlled by the choice of Rendering Intent.

Using good Colour Management protocols, Colour Matching becomes a sophisticated and almost universally available procedure, which allows good continuity of appearance between input, display and output whether in house or with other compliant users.