If you're thinking about implementing color management in your wide-/grand-format print shop, the first question you might want to ask is: Just what exactly is color management?
In answering what color management is, it might be helpful to start by answering what it is not. Color management is not color matching. It's not color manipulating. Color management is not printing a bunch of swatches and matching one of those swatches to the color you hope to print.
Color management isn't any of those things because in actuality color management isn't color management at all. It's numbers management. That's because once color goes into a computer, it ceases to be color and becomes numbers; numbers that relate to how a color is going to be reproduced in a particular color space. What color management does is account for all the number transitions from color space to color space in a digital color workflow.
What's a Color Space?
A color space is a group of colors and some means to define them.
Color spaces are important because every device that reproduces color is going to have some colors it can reproduce, and some it can't. These colors are going to vary based on any number of factors, such as, for instance, type of media and amount of ink.
The colors a device can reproduce are known as its gamut. Once you have colors in a gamut, you need some way to define them. If you define them as red, green, and blue values, you've got an RGB color space. If you define them as cyan, magenta, yellow, and black values, you've got a CMYK color space. And the values, in digital imaging, are represented as numbers. That is, after all, what "digital" means. Further, RGB and CMYK are the spaces we wind up using in this industry not out of choice, but out of necessity. Necessity because RGB and CMYK are the colorants our devices use to reproduce color. If you're going to attempt to manage color, you have to have a way to quantify how every device in your workflow reproduces color with its colorants in every situation in which you use it.
Next, there are two distinct definitions of color spaces you need to consider in implementing color management.
There are standardized "working color spaces" in both RGB and CMYK. They represent approximations of how various devices might reproduce colors, but they're not representative of any particular device. In addition, there are "device profiles" which can be RGB or CMYK depending on the device in question, that are unique to the situation and the device with which they were created. These are your specific device profiles—monitors and printers, for instance—in your workflow.
Both standardized working color spaces and device profiles are defined to all your applications that are "color aware" (that can use color management) as ICC profiles.
What's an ICC Profile?
An ICC profile is a computer file that tells color management engines how to render color into a particular color space.
Every device in your shop produces color from some set of primary colors, in some particular way. Each particular way is going to vary depending on certain factors, and each particular way is going to be different. Since each way is different, somehow or another each way for each device needs to be calibrated for each of its color reproducing conditions—such as media, ink resolution and density for your printers, and such as gamma, white point and luminance for your monitors—and then characterized (profiled.)
What all this boils down to is that while your shop and all the color reproducing devices and situations in it are unique, the rest of the world is not your shop. So your job, and the job of color management, is to get the colors of the rest of the world into the color spaces of your shop with its color information uncorrupted and hopefully undiminished. This is accomplished by moving files from however they came to you from the outside world into first your standardized working color spaces, and then into your unique device color spaces (ICC profiles.) It's how and when you make these color space moves, and how good your device profiles are, that will determine how well you do the job.
Implementing Color Management
Here are the overall steps necessary to implement color management:
- Determine every working color space in your workflow.
- Set all your applications to use the working color spaces you've determined.
- Implement a set of systems and procedures to deal with bringing outside-generated files and images into your color workflow.
- Calibrate and characterize (ICC profile) every device in your workflow in every condition with which you use it.
- Put each of the above-created ICC profiles in its proper place or places to use when needed.
- Set up all conditions in all your applications and print stations to use the workflow you've implemented.
You can loosely think of your color workflow as comprised of the color spaces that are its component parts. The actual progression of color spaces your image is going to go through are:
- Inception color space: The color space in which an image was created. This might be a camera profile or a scanner profile or simply the working color space of the application in which it was created.
- Working color space: The color space used to do any editing or alteration to an image.
- Output color space: Usually in a large format shop the final printer-media-resolution combination ICC profile.
These are the color space transitions your image goes through, but there are two other color spaces you’ll need to account for in a color-managed workflow as well:
- Viewing space: Your monitor profile.
- Proofer space: The color space of any printer you use to make proofs.
These color spaces are the color spaces you'll need to define, characterize and install in order to implement color management in your shop. So the first thing you have to do is make some decisions about what working color spaces you want to use, as they will become the backbone of your color workflow.
There's certainly plenty of confusion here, and many competing opinions, but basically you need to decide if you want to work mainly in RGB or in CMYK, and then you've got to decide which RGB and which CMYK color spaces you're going to use as your workflow color spaces. This is absolutely crucial. If you move from application to application and you don't have all your color spaces set up the same, you'll get color shift with each move.
Time to Profile
Once you've decided on your working spaces, the next thing you're going to need is profiles of all your printers in all of the conditions in which they print. And for that you're going to need to get hardware, software, and a lot of knowledge, or someone with hardware, software and a lot of knowledge to come and do this for you, or teach you how to do it.
If you want to wade in alone, the first thing you've got to consider is hardware and software. If you want to make monitor profiles, you'll need to get a colorimeter or a spectrophotometer. If you want to make printer profiles, you’ll need to get a spectrophotometer. There are several models of each out there from which to choose. Some are excellent, some are okay, and some suck.
Then there's software. There are a lot of ICC profile-making software engines out there; some are excellent, some are okay, and some aren't good at all. If you're using a RIP, it may have one of these engines bundled into it or it may not. If it does, then you can use that one. If it doesn't, then you've got to choose between one of the others out there, buy it, and use it.
Basic bottom line on all hardware and software is that it's pretty linear that you're going to get what you pay for. Spectacular color on the cheap is not an option.
Next you need knowledge. If you're serious about getting knowledge and doing color management right, you'll come out leaps and bounds ahead if you hire someone to teach you. There's a lot to it, a lot of it is going to be unique to your environment, and it all matters.
However you arrive at getting your printer profiles, once you've got them, you've got to get them in place and set up to accomplish a handoff from your design applications to your printer while keeping your color information from being corrupted. Naturally there are two pretty basic rules of thumb here: First is that you don't want to corrupt your color in the handoff, and second is that the closer the information in your printer profile is to how your printer actually prints, the closer your color is going to be to that ideal.
At this point, you're getting pretty close to home. If you understand and account for your inception color spaces, have your working color spaces set up correctly, are using correct printer color profiles and have the handoffs set up correctly, you've got an intact and correct color workflow. If you're viewing through a well-profiled monitor, then you're also seeing your images in their working spaces correctly.
The Final Piece—Proofing
The final piece of the color management puzzle is proofing. You can either 'soft proof' or make a printed proof—or both, of course—but the process is the same in either case. You've got the color space of your final output device, and you've got the color space of your proofing device. What you want to do is tell the one device--monitor or proofer—to simulate the other device—your final output device. Just how to do this varies depending on applications, but every "color aware" application as well as every RIP has some way to do it.
Keep in mind that device profile making is very much an art, and it's just possible you may set all this up and still achieve unsatisfactory results. That’s because unfortunately a bad ICC profile is still a valid ICC profile, which will be perfectly content to render color badly. If you populate a proper workflow with bad profiles, even though the workflow may be correct you'll still get substandard results. However, that does not mean color management doesn't work. It does. Set up correctly, and with first-rate professionally-made profiles, it works spectacularly.
Also keep in mind that love-it-or-hate-it, color management is always there and always on. Even if there's a switch that says you can turn it off, you really can't. Because--once again—once it's in a computer your color isn't color anymore, it's numbers, and the numbers have to relate to something. What digital color management does is tame and control the numbers, and tell them in all cases to what it is they relate. And the more you have the numbers working for you instead of against you, the more productive your shop is going to be.