為什麼色彩管理很重要？

色彩管理為一套作業流程，由一種擷取色彩的輸入裝置來進行。目的在於讓所有媒介都能呈現準確的色彩與色域，例如螢幕上所顯示的內容，或是影印出來的圖片、文件都能有一致的色彩。

透過下面這張「鳥兒站立在霜白圍牆」的相片便能很好地說明為什麼色彩管理有其重要性。

「鳥兒站立在霜白圍牆」於相機觀景窗中所看見的樣子

一般顯示器的藍色色版飽和度較高，其所呈現的相片會偏向冷色系。

該照片於一般商用筆記型電腦的螢幕中所看見的樣子

注意下面這張相片的白色部分，其所呈現的白並非「紙張的白」；眼睛的黑色部分也呈現為「混濁的褐色」。

該照片透過普通的噴墨印機列印後所看見的樣子

The basic problem we have here is that each device is capable of handling a different range of colors. So while you might be able to take a photo of electric blue, most printers are not going to be able to reproduce it.

Most image devices capture in RGB (Red, Green, Blue) and have to convert to CMYK (Cyan, Magenta, Yellow, and Black) to print. Another problem is that you can’t have white ink, and so the whiteness can only be as good as the paper color.

Another problem is units. Without specifying the scale on which a color is measured, we don’t know if 100% red is near infrared or just the deepest red ink in the printer. What is 50% red on one display is probably something like 62% on another display. It’s like telling a person that you’ve just driven 7 units of distance, without the unit you don’t know if that’s 7 kilometers or 7 meters.

In color, we refer to the units as gamut. Gamut is essentially the range of colors that can be reproduced. A device like a DSLR camera might have a very large gamut, being able to capture all the colors in a sunset, but a projector has a very small gamut and all the colors are going to look “washed out”.

In some cases we can correct the device output by altering the data we send to it, but in other cases where that’s not possible (you can’t print electric blue) we need to show the user what the result is going to look like.

For photographs it makes sense to use the full tonal range of a color device, to be able to make smooth changes in color. For other graphics, you might want to match the color exactly, which is important if you’re trying to print a custom mug with the Red Hat logo that has to be the exact Red Hat Red.