Color Management: A Field Guide
Whether you are designing for print or for the web, making the leap from what you see on your computer screen to the outside world can be a tricky process, fraught with unpredictable changes and unexpected results. The web is full of information regarding color management and sifting through it can be very overwhelming. Contradictory opinions abound and it can be difficult to find reliable sources of information.
Over the last few months, Scott and I have been researching this topic extensively. With the addition of the new Epson 9900 to the studio, we wanted to be sure that our printer workflow was optimized and producing a consistent output. With the help of Kirk Economos of Meridian Cyber Solutions, we have implemented a color management system that works for us. Below we have tried to aggregate this knowledge into a simple and useful guide, designed to help you ensure your studio is set up correctly. It is not intended to be the end-all article on color management by any means — but it’s a good place to start if color management isn’t something you have previously implemented or considered.
The first step to a successfully calibrated studio does not begin with the computer. The space within which you view your computer screen can make a big difference and it’s important to be aware of the factors at play.
Light levels are a primary concern. The main thing to keep in mind is that you are trying to avoid screen glare, fluctuations in light, or any unusually bright sources of light; whether from a lamp, window, etc. All can affect the dynamic range of the monitor and alter your perception of the images on your screen. Ideally your workspace is lit by a consistent artificial source (not pointed directly at the screen) and is not overly bright or dim. Spaces lit primarily by daylight can be especially problematic given the large variation of both light intensity and the color cast of the light. Not everyone can achieve optimal settings of course, but you want to try and maintain consistency at the very least. Designing with your laptop on a sunny beach — for example — will probably not yield the most predictable results (although we’re all for experimenting!).
An additional step you can take to ensure ideal lighting conditions in your workspace is to paint the walls with Munsell 8 Gray. This paint is specially formulated to have a flat spectral response with no color bias. Unlike other hues, this type of gray will not affect your perception of other colors in the spectrum. It creates a “pure” and neutral viewing environment. You may have noticed this color on the wall of photo studios and print shops. Additionally, changing your desktop color to a shade of neutral gray will help for the same reasons.
The state of your workspace is important not only for screen viewing, but also for evaluating printouts. Often times what appears to be a poor color reproduction by the printer is actually the result of irregular lighting conditions. Many print shops have light booths to ensure that they will always have a standard viewing situation. At the office or home, just make sure you are aware of the type of light you are using to view your printouts, and that you don’t change things around too often. Many people underestimate how much difference even the slightest change can make.
Prior to researching this topic, I gave little consideration to my viewing environment and blamed all inaccuracies on my printer. While this was often a fair assumption, there were many times when the inaccuracy I was noticing was the result of viewing the printout at different times of day with different light sources. Sounds simple enough, but it’s easy to overlook.
So what light do we use to proof? Despite all the suggestions above, we are still using daylight from our studio window. For the record, this is far from ideal and we plan to invest in a Just Viewing Station shortly.
If you are interested in other aspects of the optimal graphic environment, most are contained with the ISO 3664:2009. The International Organization for Standardization sells this document as a PDF in an effort to establish a consensus on viewing standards.
Once your space is set up it’s time to calibrate the monitor itself. If you are on a Mac, there is a very easy to use onboard calibration tool. It’s manual and conducts a variety of visual tests to determine how you perceive certain colors and contrast scenarios. You can find it under System Preferences –> Displays –> Color –> Calibrate. Make sure the monitor has been on for at least 30 minutes before doing this.
The problem is that this test relies on the human eye to make effective judgments. Anyone who has ever seen this knows that the eye is not to be trusted. It is an important step regardless, if only to establish a base level of calibration, but it is not satisfactory if you consider yourself concerned with precise and accurate color readout. An alternative to this manual hardware calibration is a third party device that calibrates it for you.
There are a number of mechanical calibration tools that will analyze your monitor and calibrate it to your workspace conditions. They are far more reliable than onboard manual calibration, but can be a little pricey. One example is the Spyder from Colorvision. It’s very easy to use; you basically just hang it in front of your monitor, run the software, and wait for it to finish checking how all the colors are displayed. From there, it will generate a profile based on its findings. If you are running multiple computers, a mechanical calibrator can be a good tool to ensure that your monitors are all calibrated to the same standard. Here at the studio we use the Colorvision Spyder 2 and it’s been cranking out reliable calibrations for years now.
There are two basic classes of hardware calibration devices: colorimeters and spectrophotometers. Those are two big words and you really don’t need to understand them. Typically, colorimeters are less complex devices and thus cheaper than spectrophotometers. Spectrophotometers are more complex — and in theory more precise — but will cost you more. The Spyder we use is a plain old colorimeter and it’s served us well.
On a side note, the color response of LCD monitors will shift naturally over time and as they get older, the rate at which they shift increases. You should calibrate every 2-4 weeks to keep your display in the sweet spot and because of this, a mechanical calibration system will save you a lot of time over manual methods. The bottom line is that it’s well worth it to own at least a basic mechanical calibration system.
Color Mode & Application Settings
This is where it starts to get tricky. Most designers are set in their studio space and have calibrated their monitors at least once. Unfortunately, there are many other steps along the way to a full system calibration (printer, web, software, monitor) where you can mess things up.
Everything begins with the Color Mode (RGB, CMYK, Grayscale). The most basic difference is that RGB (used on screen) is an additive mode and CMYK (print) is a subtractive mode. The important thing to understand is that your screen is using RGB to emit color, and your printer is using CMYK to reproduce color. Just about every other device used to capture or reproduce images is working in RGB (scanners, digital cameras, our eyes etc).
Illogical as it may sound, when working at home, you want to send your printer (which is a CMYK device) RGB images to print. The conversion occurs within the printer and the software addresses the printer as an RGB device. This is where — at least amongst the student population — much confusion is generated. Given the fact that the printer is technically producing CMYK output, it sounds like the logical mode to use is CMYK. This is not the case. Not only is the printer designed to receive RGB output from the software, but you would also be shortchanging yourself of certain colors that both RGB and the device can address that are outside the gamut of the CMYK color mode (within the software).
One exception is when you are working with a commercial printer. They often prefer for you to make the CMYK conversion on your end (prior to printing), but it’s always best to check, as they might have specific target profiles or settings they prefer. This article is focused on color management at the home studio, and will not address the specifics of working with outside vendors.
Within a color mode, you have a color space. You are probably familiar with a few; Adobe 1998, sRGB, ProPhoto RGB, etc are all color spaces within the RGB mode. Like a box of crayons, some color spaces are capable of representing more colors than others. Adobe 1998 is widely regarded as one of the better color spaces when working with an inkjet printer. While it is not the most substantial in terms of the amount of color it can display (ProPhoto for example can do more), it is widely adopted and is a good all around compromise.
Along with Adobe 1998, sRGB is one of the most commonly used (especially on the web, not really for prosumer or professional print work). The sRGB color gamut encompasses 35% of visible colors, while Adobe 1998 covers 50%. The sRGB space is a better fit for the web because most browsers cannot display all the colors of Adobe 1998 correctly. You end up getting washed out looking images as the browser tries to fill in the gaps. When choosing a color space, it will largely depend on where you will be outputting the image to.
When you create or capture and image, it is tagged with an image profile. This profile is embedded within the image and tells the software what color space the image is using. A device profile — such as the monitor profile you create during monitor calibration — reproduces color independently of the image. Every device you use — whether it be a scanner, printer, monitor, or otherwise — will have its own profile (basically a formula that tells the software how the device will render the color in the file). So for example, if I have an image I’ve created in the Adobe 1998 color space (image profile), I can have multiple different interpretations of this image based on my multiple device profiles. Ideally, my devices are calibrated and the visual representations of the image profile are as close to consistent as possible.
In a perfect world, all of our documents would be created using the right profile, but of course this isn’t always the case. If you need to change color spaces in an existing document, use Edit –> “Convert to profile” (shown above). This will ensure that the correct numeric codes are always being interpreted and the colors are being reproduced accurately. If you “assign” an inconsistent profile to an image, the color output will be incorrect. It is best to use the convert to profile command (as opposed to assign profile) as converting actually modifies the numeric codes associated with an image. Assigning a profile only changes the way existing data in the image is interpreted locally, on your system, and does not alter the image data itself. So let’s say you create a document using Adobe 1998 and later assign another profile, such as sRGB. You now have two profiles stacked which will lead to an inaccurate view of the image. Once you save the document and send it off to the printer, the assigned profile (sRGB) will be lost and the output will not reflect what you saw on your screen. Assigning a profile is only advised when opening a document which does not have a color profile attached and is for local preview purposes only.
Much of Scott’s work is created in a CMYK space because a lot of it ends up being printed commercially. So when we’re printing his work to the Epson or outputting for web, we must first convert to the appropriate profile. If necessary, we then make adjustments to the file to compensate for any shifts resulting from the conversion. When printing to the Epson inkjet, we generally convert to Adobe RGB (1998) and for web output we use sRGB (IEC61966-2.1).
In Photoshop, choosing the setting “North American Prepress 2″ (Edit –> Color Settings) will get most of the settings in proper shape (Adobe 1998 color space etc). It will also allow Photoshop to recognize when a file is opened with another colorspace at work, and it will ask you what to do. In these cases, you want to convert the profile to match the Adobe 1998 setting. This will also ensure that you are always aware of what space you are in and are alerted if you get a file that is not consistent with your settings — which seems to be the case more often than not.
Assuming you have all of your settings correct, you are ready to print. As mentioned earlier, inkjet printers prefer the file to be created in the RGB space. The printer does the conversion to CMYK mode with the help of an attached ICC profile. This workflow will preserve as much detail as possible.
Assuming correct color space settings, the printer workflow that we have been using is as follows:
2. Click “Page Setup” and make sure you are “Formatting for” your specific printer and the correct paper size.
3. Do not “Scale to fit media”. Make sure the image size meets the desired output paper size before hitting print.
4. Make sure ‘Color Handling” says “Photoshop manages colors”. This ensures that the colors will be as close as they can be to what you have been viewing in Photoshop. You are also specifying that you do not want the color to be managed by the printer. You do not want to apply more than one profile to your print job.
5. Make sure the “Printer Profile” matches both your printer and the eventual type of paper you are using* (see below for more info). (RW = Radiant White, PK = Photo black ink). For example, for the Epson R2400 printing on enhanced matte paper, I will choose the “SPR2400 Enhanced Matte” setting.
6. Hit Print and go to the second dialog box.
7. Very important! Under “print settings” turn OFF color management by the printer. If left on, this will apply a second color profile — in most cases, applying two profiles to a job is worse than applying none at all. You would undo all the color consistency you worked hard to ensure. Think of it like a person with glasses putting on another pair of glasses over their own; it just doesn’t work.
8. Make sure “Media Type” is using the same paper type as your previously selected ICC profile. This setting, used as a shell, will determine the ink limits and linearization.
9. Hit Print (finally)
10. There are additional steps to consider if you are printing to a large format machine, like our 9900, but these have been omitted under the assumption that most people aren’t working with such a complex system. But to tell you the truth, it’s pretty much the same as the small ones with only a few exceptions.
Don’t forget, Turn OFF color management in the printer driver!!! You have already asked Photoshop to handle this in step 4, and Photoshop will do the conversion from the file’s color space to the devices color space correctly. Once you get output you’re happy with, most of these settings can be saved as a preset and recalled later.
*Since different papers handle ink/color differently, there need to be a lot of ICC profiles. They ensure that the conversion from RGB to CMYK is seamless and optimized for the device and eventually the paper. These profiles are usually available on the manufacturer’s website and some (such as Epson) are automatically installed with your printer drivers. Some paper manufacturers will approximate the best ICC profile to use with their paper if they have not created their own.
Ideally, it would be possible to achieve complete visual consistency throughout every part of your workflow. Unfortunately, no matter how thoroughly you adhere to color management guidelines, there will always be inherent discrepancies in how color is represented between mediums. What you should aim for is consistency; both in your output (as best you can) and your studio environment. Consistency will lead to familiarity and you will be able to compensate and make the appropriate changes to your documents to ensure they output as intended. It takes a little bit of work, but with the correct information, settings, and equipment, you can drastically improve your color management.
As previously stated, this article is not intended to be an end-all one stop shop for color management. We hope only to illuminate some of the more confusing issues and present a basic working knowledge of color management. This is simply what works for us, but your mileage may vary and there’s always another way of going about things. If you have any, questions, or would like to add anything we missed, please don’t hesitate to let us know in the comments. If you just liked the article and want to let us know, your comments are welcome too.
Thanks again to Kirk Economos for his help putting this article together and for getting our printer up and running!