My favorite analogy to explain the basic concept of, and need for, color management is the United Nation.
Consider the five permanent members of the UN Security Council – the United States, the United Kingdom, Russia, France and China. Among these five delegates are spoken four languages – English, Russian, French, and Mandarin Chinese. In order for the delegates to discuss an issue, each has a team of interpreters translating what is said by other delegates into English, Russian, French or Chinese. Thus, France’s delegate to the United Nations listen not to the actual words of Russia’s delegate but to a faithful translation by UN aides. The UK’s delegate listen in English, the US delegate also listen in English, and so on. Each member nation’s delegate speaks in his native tongue while the other delegates listen to translations in their native languages. Thus, the hard-working translators convert meticulously from one of the four different languages to another; every delegate hears precisely the same questions and words, just in different syllables.
Let’s elect some new delegates to the UN Security Council’ permanent seats. China’s seat we’ll give up to the Scanneravia. The island Kingdom of InDesign will take over for France. PDF Nation and the United States of Offset will oust the UK and the US. Instead of Russia, let’s install a delegate from the nation of the Federation of Independent Proof Printers.
We now have a new council of delegates, all of whom still speak completely different languages and still require their interpreters. But, you can’t just advertise in the New York Times classified for “scanner to offset press interpreter wanted, must also speak PDF.” How will these five delegates talk about a color photograph being moved from E6 slide to scanner, the digital output imported into an InDesign layout, and then the output sent on to proof print, PDF, and finally ink to paper? What if the discussion needs to include some or all of the other 10 UN Security Council member states. Maybe the photo needs some touch-up in Photoshopia before being flown to the Kingdom of InDesign? Or, after PDF Nation ships the document containing the photo, will that document pass through the Provence of the Web Press or need to be discussed by the myriad dialects of Printeria’s Monitors?
How are all these delegates supposed to accurately discuss the project, and each contribute to its completion, if none of them can understand any others interpretation of color? They can’t! They need interpreters to faithfully translate from the language of one into that of another, to tell the Kingdom of InDesign what Scanneravia is saying about red, green and blue or hue, saturation, and luminosity. Without a translator, one might swap purple for blue, mix some green into the yellow, or turn bright white into a dirty, aged cream.
That is where a color management system (CMS) comes in. Once a CMS learns the unique language of each speaker as well as the language of the listener, it can translate between the two. First, the CMS must be taught each language by the delegate (device) in the form of an ICC profile. The ICC profile is a Rosetta stone, defining a given device’s color language in the universal but unutterable dialect of math. Given any two of these ICC profiles, the CMS can translate color described by one in its native language to the native language of another. The end result is that, although two incompatible languages are used, the CMS ensures that both devices see, render, and maintain the same colors, hues, and shades.
Color management isn’t perfect. Not every device is capable of seeing all the same colors. One may clip the reds, another the blues; one may see fewer values between black and white than another; just as CMYK process inks simply can’t reproduce certain shades, like pure blue.
Without color management, however, you have absolutely no predictability in color input from source (a camera, scanner or software) onto screen, through touch-up (Photoshop), into layout (InDesign) and then to output (PDF, print or Web).
Did your digital camera accurately capture the full range of vibrant oranges in that field of flowers, or did your minor defects in the camera’s CCS encoder or JPEG renderer over-saturate the yellows by 6%? Without an ICC profile created for that camera, you’ll never know. When you bring the image into Photoshop, you’ve introduced two completely new devices with their own unique methods of interpreting and rendering color – Photoshop itself and your computer monitor. Without color management, both could be completely misinterpreting data coming in form the photograph. You could be punching up the blue in the sky over the flowers only to realize a week later when you get the printed pages back that you actually turned the sky purple.
The purpose of color management is to make the visible result of every color input device – camera, scanner, software – match the visible result of every rendering device – monitor, software, proof printer, printer – and both match the original all the way from initial capture to final output.
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