“To err is human, but to really foul things up you need a computer,” said Paul Ehrlich, and he could easily have been describing color management. It’s arguably the most baffling computer task to wrap your mind around.
Why do we need Color Management? It’s a system of software and hardware through which one can create, edit, view, share and reproduce visual art (here I’m concerned with photographs) in a way that provides controlled, consistent and reliable reproduction of color independently across different devices. “Devices” includes computer monitors, printers, scanners, printing presses, digital cameras, TV screens and more.
Even visual professionals find this topic daunting. It’s filled with jargon and arcane workflow recipes. Faced with the seemingly incomprehensible, most people default to doing nothing. But ignorance is not bliss; in the mix of results, some photographs print or display as expected while others get turned to mush.
Even if you to hire the most talented and knowledgeable professionals, and they deliver superb photos to you, you can undo all their careful work simply by opening and saving the photograph in your system.
Even if you have little or no interest in being a tech guru, you should take a few minutes to set up color management in Photoshop. Small mistakes can snowball into bigger ones that require tedious or expensive corrections.
The bad news: even if you hire the most talented and knowledgeable professionals, and they deliver superb photos, you can undo all their careful work simply by opening and saving the photograph in your system. That’s right, just by opening and saving. It’s important to set properly the default preferences of your programs.
The good news is that you can set the preferences so that color-managed photographs and art work keep their color management settings. And you will be able to view, save and send files downstream to your creative professionals, service bureaus, offset printers and web site designers with confidence.
Background Of Color Management
Open standards for color management were developed by the ICC, or “International Color Consortium.” You can read more about the ICC here.A color profile tag or ICC profile is a small piece of software that is embedded in image files to convey the color appearance of the raw numbers. It’s a kind of “Rosetta Stone” for color; the color profile tag tells a program that can read it the meaning of the color numbers the file contains. Repeat, the meaning of the numbers. Depending on the profile attached, the exact same digital file can mean radically different color appearances.
A color profile tag may be attached to digital photographs upon creation or at different stages in preparing a photograph for reproduction. If no profile is attached, or the profile is stripped away, different software will make assumptions about color appearance which can be quite wrong.
The majority of computer software that can open and display image files (JPEG, TIFF, PICT, etc.) do so with little or no color management and without honoring embedded ICC profiles. Examples of these programs include Internet Explorer, Flash, e-mail programs, MS Word, early versions of Adobe products, QuarkExpress and many more. It’s pretty typical that photographs or artwork being passed around for approval or review in any corporate or business environment will find their way in and out of these programs, where all color management information will be at best ignored and at worst stripped away. There is little or nothing you can do about the behavior of these programs except to be aware and try to minimize the inevitable inaccuracies.
First: Do No Harm
There are a number of file-browsing programs now that offer speed and accuracy in viewing digital image files: Adobe’s Bridge and Lightroom, Apple Aperture, PhotoMechanic, Google Picasa (color management must be enabled, see here), and more. Out-of-the-box today, these programs are capable of strong color management controls. But before and after photographs go through these programs they may be delivered, shared or transferred in and out of other software with the potential to create or amplify color problems.
Adobe Photoshop is the most robust and most likely program you will use for opening, adjusting, creating and saving photographs. Its color management preferences apply powerful leverage to your settings, whether right or wrong.
There are three levels of concern: first, do no harm; second, save and send files downstream properly; and third, power-user control. Most people need only to address the first two, which are easy, free and my topic. Power-user color management is beyond the scope of this article.
What kind of harm can be done if your preferences are wrong? Let’s use a typical assignment as an example, head shots of the company executives. Your photographer has given you a disk of photos, prepared very carefully. You open the photos, view and make your selections, send JPEG copies via e-mail and save the photos to your hard drive. Pretty simple? If you’re not color managed, and depending on your program and preferences settings, very bad things can happen. Let’s look at two too-common outcomes. I’ll use a portrait of my daughter, Gina, to illustrate.
- Profile Stripping: Without telling you, an improperly configured version of Photoshop, or many other programs, can remove the ICC profile from the color managed photograph.
Hidden Conversion: Photoshop might convert photos into to an unknown RGB color space, or a printer might convert into unknown CMYK space at the wrong point in the chain with devastating results.
In the profile stripping example of our head shot scenario, the photographer prepared the portraits in ProPhoto RGB and sent you JPEG files that were properly tagged with an icc profile. You handed the photos off to your web designer, who is not color managed. When dropped into your web site the photos look very dark, mushy and with ugly color. The digital files are unchanged, but the icc profile tag that conveyed the meaning of the numbers was removed. The web designer then compounds the problem by attempting to re-edit the images on an uncalibrated system. Many hours time can be wasted and regaining accurate color is almost impossible.
In the hidden conversion outcome of our head shot scenario, errors can unfold a few ways: (1) your photographer mastered the photos in a managed color space, but when you opened the photos and saved them your system converted the photos into a bad RGB default space, such as a monitor profile; or (2) your photographer prepared your files in CMYK but your system converted them into RGB without telling you; or (3) you sent the photos to an offset printer in RGB. The standard policy of many offset printers is to feed everything directly into the plate-setting RIP. The RIP is set up for CMYK only, is not color managed, and does a “black box” conversion of any RGB files into a really bad version of CMYK. The result: garish, off-color with red-green crossovers and harsh contrast.
To do no harm, set your preferences correctly. Small differences in preferences locations and dialog boxes exist from Photoshop CS2 through CS5, but to set you color management preferences follow the following recipe:
1) Launch Photoshop with no document open.
2) Under the “Edit” pull-down menu, go to “Color Settings.” There are a number of important settings here.
3) On the right of the dialog box, select “More Options” if it is available.
4) At the top center Settings pull-down menu, select the most universal default, “North American General Purpose 2.” You will see the Working Spaces with the RGB color space “sRGB,” the CMYK color space “U.S. Web Coated (SWOP V2),” the Gray space “Dot Gain 20%” and the Spot to “Dot Gain 20%.” Color Management Policies should show “Preserve Embedded Profiles” enabled for all. This is extremely important so that your computer does not alter the color of files you open and save (more on that later when saving.) Leave the Missing Profiles boxes, particularly “Ask When Opening,” unchecked (disabled). If you check it, no harm will come, but you will have an annoying number of dialog boxes popping up when you open files with different color profile settings than your system. You might want to enable “Ask When Pasting” when you know more at a future date, but leave it alone for now.
5) The third section down, Conversion Options, should show the Engine as “Adobe (ACE)” and the Intent “Relative Colorimetric.” Also checked (enabled) will be “Use Black Point Compensation,” “Use dither (8-bit/channel images)” and “Compensate for Scene-referred Profiles.”
6) Leave the Advanced Controls unchecked (disabled) for “Desaturate Monitor Colors By” and “Blend RGB Colors Using Gamma.”
If you have an older program and don’t have “North American General Purpose 2” as I’ve described, you should be able to select these same settings in the individual drop-down menus and then save a custom setting file for the group.
7) Click OK to close the dialog box. This screen capture shows the settings:
Finally, quit Photoshop. Now when you restart the program, these settings will be the new default.
Set up this way, when you open any image that is tagged with an ICC profile, Photoshop’s built-in color management will be used to display the image properly. Your ability to accurately view the photo will be limited by the quality and color-management status of your monitor, but the underlying file accuracy will be preserved.
Your monitor requires a separate software and hardware package to bring it into compliance with ICC viewing standards. You should not make color edits to photographs unless you’re quite sure you know exactly what you’re doing. Most off-the-shelf flat panel monitors are driven at much too high a brightness (luminance) level. Photos will appear over bright and washed out, and when you “correct” them you will be making them too dark for print.
To save your photos accurately for other users or service bureaus, there is one thing more you must do: when saving files, in the Save dialog box always check (enable) the box Embed Color Profile.
This preserves color management in the round trip through your system. Sending your photographs downstream to your designers and service bureaus requires you to answer another question accurately: RGB or CMYK?
CMYK is needed for offset printing and some in-house laser printers. The vast majority of everything else is best left in a color-managed icc-tagged RGB. Professional RGB color spaces can contain vastly more individual colors than CMYK spaces, even exceeding the range of human vision. There are significant advantages to doing late-binding color conversion from RGB to CMYK. When you convert to CMYK spaces, information is thrown away that cannot be retrieved, and every printer will have different standards for ink density, black plate generation, and a host of other specific requirements. Editing color in CMYK is difficult, non-linear and non-intuitive. Each round of editing will degrade image quality.
Think of RGB as a fully equipped kitchen, with every recipe and every ingredient. CMYK is like the cake you bake for a party; each one is unique. You make it for a specific function but you don’t expect to keep it around forever. If you need CMYK, work closely with your printer and design professionals to make your conversions properly, and save as copies to preserve your original RGB files.
To explain each of these settings in detail, I recommend any of the Real World Photoshop books, and other reference works for advanced study. Web links follow.
You don’t need to know all the mechanics in order to take advantage of correct preferences. Of course, power users such as graphics professionals and photographers will have very compelling reasons to make other choices at different stages of the process, but the default settings for the average user should be as I’ve described.
Now that you are color managed, you can use Photoshop to open, review and save photographs with their color profiles preserved and utilized to display as accurately as your monitor makes possible, even exotic RGB or CMYK color spaces. When you save files to your hard drive, enabling Embed Color Profile, nothing has been changed. The photo stays in the color space as it was provided to you, and the meaning of the numbers has been preserved.
The settings described above are the best (or “least unsatisfactory”) choices for everyday users. Mismatches between color profiles and program rendering assumptions are the most common problem with photographs used in different programs. The “sRGB” color space, though in no way the largest or “best” RGB color space, has become the de facto standard color space for the World Wide Web, e-mail programs, Windows programs, desktop printers and virtually all unmanaged color devices. Any digital photos intended for these programs (or which will be viewed by decision makers using these programs) should be prepared in or converted to the sRGB color space prior to delivery. You will want to make sure your service bureau and creative providers know how to deal with color-managed digital images.
I hope you can see that even modest use of Photoshop requires you to set up preferences correctly. Follow these steps and you’ll get the maximum quality from your image files.
I welcome all feedback and suggestions. If there are other topics you’d like to see discussed, or for specific problems I might be able to help you with, you can post to this forum or e-mail me at firstname.lastname@example.org.
Ready to become a power user? Try subscribing to the Colorsync list (digest recommended):