A basic color space conversion is simple. Identify the source, identify the destination, let the CMS do its thing, and color is accurately communicated from one color space to another. In the laboratory environment, color management is a perfect system; it works every time. However, in its day-to-day implementation, color management is complex.
Why is this seemingly simple task so tricky? How can things get so complicated?
I like to use the allegory of the 50 switches.
Controlling a room light involves flicking a two-position switch; it's either on or off. Very simple. However, imagine that for the light to come on, there is not one switch but 50 switches, and each switch has to be set precisely, either on or off, in order for the light to turn on. And let's throw in a wrinkle: each switch is in a different room controlled by a different person. If 49 switches are correctly set but one is incorrectly set, the light won't come on.
This is the world we live in. In the average RGB-to-CMYK workflow, there will be numerous people handling the file, each with a different grasp on how color management works. There are numerous software programs that will host the file—Photoshop, InDesign, Quark, Acrobat, a variety of RIPs—and each has a different way of implementing color management. Each one of these factors is a variable. When you start piling variables on top of variables, it's deceptively easy for one of the switches to be set the wrong way, resulting in very unpredictable color. What started out as a simple one-step move can easily turn into a spider web of inscrutability.
Here are just a few examples of one switch being thrown the wrong way:
- A partner saves a file without embedding a profile.
- A partner assigns a profile instead of converting to a profile.
- A partner chooses the option Don't Color Manage This Document.
In each of these cases, the integrity of the entire color management chain is broken, and accurate color is no longer being communicated.
When you find yourself entangled in this web, review the basics and logic of the process:
- Every file must reside in a color space and be tagged with the profile describing that color space. Remember, RGB triplets only have meaning in the context of a particular color space. A file without an embedded profile cannot generate predictable color.
- Always know in which color space your file resides.
- When converting, make sure the Source-to-Lab-to-Destination path is clear and unambiguous, and intelligently manage the change in gamut.
Remember, color management is communication, between both partners and files.