In an earlier article, we have talked about the three stages of workflow for photographers and designers, so we have a basic understanding of how color management works in principle. Now, we can take a closer look at how to incorporate the ICC profiles in a practical workflow.
The first step in the workflow is content creation, and for photographers, it means taking photos with their beloved cameras. If reproducing the original scene is the goal of their work, then some extra precautions should be taken care of at this stage.
It is very understandable that ambient light could change the mood of the photos greatly. Hence, we need to deal with lighting first to preserve the colors we seen at the scene. With the use of exposure meter, photographers could determine the right aperture and shutter speed settings so the photos are not over or under exposed. The exposure meters are designed in a way to deliver the same exposure level across various lighting conditions. Once we have the exposure set, now we need to put a ‘reference’ in the scene to know how to recreate the colors at the time of photographing. The most widely used ‘reference’ is a color chart containing 24 color patches called ColorChecker® and was designed for this purpose. There are different varieties of the color patches, and one is particularly useful is called ColorChecker® Passport. Figure 1 illustrates the different varieties of the ColorCheckers®, and Figure 2 illustrates how to use the ColorChecker® Passport when capturing a photo.
Figure 1.: Different varieties of ColorChecker®: White Balancing and Gray Balancing ColorCheckers® are on the left, and 24 colors ColorCheckers® are on the left.
Figure 2.: How ColorChecker® Passport was used at the time of capturing.
In theory, we could also use the camera ICC profile to obtain the correct colors from the scene. However, ICC profile will only work best if the capture condition matches the condition when the profile was built. For example, the lighting condition (color temperature and light level), the camera body and lens combination, and the aperture, shutter speed, ISO and color mode settings all has to be exactly the same. It is nearly become impossible to create ICC profile under these constraints, so a more practical way is to utilize the ColorChecker® when capturing the photos, and use the ColorChecker® to create a profile. The profile created is not necessary an ICC profile, but it serves the same purposes as ICC profile for preserving colors. The ColorChecker® Passport comes with its own software to extract the colors patches to generate a DCP file (Digital Camera Profile); the process is illustrated in Figure 3. The DCP file could later be imported into Photoshop or Lightroom to simulate the capturing condition recorded from the camera.
Figure 3.: The ColorChecker® Passport software will automatically identify the color patches and use them to generate a DCP file.
Now the second stage in the workflow is to enhance the photos. This is the stage where monitor plays a very important role since all final colors are decided here. A color management monitor with hardware calibration capability is definitely the first choice. Needless to say, a good monitor also requires proper calibration. But what are the targets a photographer should calibrate their monitors to? Here, we provide a set of typical calibration targets for reference in Table 1. This set of calibration targets will suit the needs for most photographers.
Table 1.: Set of calibration targets suitable for most photography wor
|Color Gamut||Color Temp||Luminance||Gamma Curve||Black Level|
After properly calibrating your monitor with the above calibration targets, an ICC profile of your monitor will be generated. This ICC profile is an important one to pay attention to, and should be used in Photoshop as your default RGB Working Space. Please follow the steps to change the setting:
1. Go to ‘Edit’ -> ‘Color Settings’ (as shown in Figure 4).
2. In the pop-up window, select your monitor ICC profile from the drop-down list in RGB Working Space (as shown in Figure 5).
3. Select ‘Convert to Working RGB’ under Color Management Policies (as shown in Figure 5).
Figure 4.: Access to ‘Color Settings’ in Photoshop.
Figure 5.: Change RGB under Working Spaces with your monitor ICC profile.
The reason of setting your monitor ICC profile as your RGB working space is because you are working with a physical monitor to edit/modify the colors, and by doing so will allow all your adjustments to be truly reflected from your monitor. And in order for this to work, you also need to select ‘Convert to Working RGB’ under Color Management Policies. Of course, it will be safer if you click ‘Ask When Opening’ for Profile Mismatches and Missing Profiles.
One question you may ask is, “where are my ICC profiles?” or “why I don’t see my monitor profile in the drop-down list?” The answer to these questions is “there is a specific folder for ICC profiles and you need to put your ICC profiles there to make it available for the drop-down list.” So where is that specific folder? Windows OS and Mac OS have differnet locations for the ICC profiles, and are listed in the following:
• Mac OS:
• \Users\[User Name]\Library\ColorSync\Profiles
where [User Name] is the your user login name
The folder location is OS dependent, but is not version dependent. So you could find this folder in different versions of Windows OS or Mac OS. Usually when the monitor calibration is done, the ICC profile will be automatically save to the above location. But if you have other profiles need to be ‘installed’ to your computer, then just simply copy the ICC profiles to the above folder and restart Photoshop, and you will see the ICC profiles are now in the drop-down list.
After all the editing work has been done, now it is the time to distribute your work (photos) to the world. But before doing that, you would want to make sure everyone else is seeing the same colors as you do, right? Here the concept of ‘soft-proofing’ comes to play. For example, if you will send your photos to be printed, you can see the simulated colors from the printer before you actually print the photos. This could be done in Photoshop by utilizing the printer ICC profiles with the correct paper and ink combination. The steps are summarized in the following:
1. Obtain the printer ICC profile with correct paper and ink combination. It is essential to get right ICC profile for the paper and ink you are using. Printer ICC profile could be obtained from printer’s driver and manufacture’s website, ask your local photo lab or print shop to provide the profile, or generate printer ICC profiles from 3rd party profiling software. There are number of sources in the internet which could provide detail instructions for generating your own printer ICC profile, so we will not go into details here.
2. Copy the printer ICC profile to the ICC profile folder listed above.
3. Restart Photoshop if the application is in used before you done the copy operation.
4. Go to ‘View’ -> ‘Proof Setup’ -> ‘Custom’ (as shown in Figure 6).
5. In the pop-up window, select your printer ICC profile in the drop-down box next to ‘Device to Simulate’ (as shown in Figure 7).
6. Select ‘Relative Colorimetric’ in ‘Rendering Intent’ drop-down box (as shown in Figure 7).
Figure 6.: Access to Custom Proof Setup in Photoshop.
Figure 7.: Select the printer ICC profile in the drop-down box next to Device to Simulate.
7. Now you will see your photo has changed its appearance. You can select and deselect the check mark next to ‘Preview’ to enable and disable the simulation function. Or you can also close the pop-up window by click on ‘OK’, and press ‘Control+Y’ (Command+Y for Mac users) to enable and disable the simulation. Figure 8 illustrates the ‘before’ and ‘after’ simulation effect in Photoshop.
8. If you would like to correct some colors under the simulation, you can simply go ahead to process the photos as usual, and you will see the effect on the print-out.
9. If you are satisified with processing, now the photo is ready for print. Before you send your photos to your photo lab or print shop, it is always a good practice to convert your photos to your monitor ICC profile and embed the profile with your photos. In this way, you local photo lab or print shop could see what the photos are like on your monitor.
Figure 8.: ‘Before Simulation’ (top of the figure) and ‘After Simulation’ (bottom of the figure).
Most of the photos nowadays are not printed at all, but published mainly on the Web. This will be much more tricky to deal with than the print-out case if you would like the colors to be correct for everyone. We have no knowledge of what kind of monitors that the viewers might have, therefore, we could only assume sRGB monitors will be used. So it is viewer’s responsibility to make sure their monitors are comply with sRGB requirement. Before publishing the photos on the internet, let us convert the photos to sRGB color space. The steps are shown in the following:
1. Go to ‘Edit’ -> ‘Convert to Profile’ (as shown in Figure 9).
2. In the pop-up window, select ‘sRGB IEC61966-2.1’ in the drop-down box under ‘Destination Space’ (as shown in Figure 10).
3. Click on ‘OK’ to close the pop-up window.
4. Go to ‘File’ -> ‘Save As’.
5. Click on ‘Embed Color Profile’ in the ‘Save As’ window (as shown in Figure 11).
Figure 9.: Access to ‘Convert to Profile’ in Photoshop.
Figure 10.: Select ‘sRGB IEC61966-2.1’ in the drop-down box under ‘Destination Space’.
Figure 11.: Click on ‘Embed Color Profile’ to embed the sRGB color profile to the photos to be sent out.
In this article, we have learned how to use ICC profile to maintain the color consistency during photographer’s workflow. In order to capture the right colors at the scene, exposure meter and a color checker are necessary for capture the light and colors correctly. On a properly calibrated color management monitor, we could utilize the monitor ICC profile to simulate the print-out appearance or any other devices which have an ICC profile to describe. At last, we also point out before publishing the photos on the web, it is necessary to convert the color space to sRGB and embed the profile with the photos. There are also some practical tips for utilizing ICC profiles in the photographer’s workflow, for example, how to set up RGB Working Color Space, where to store the ICC profiles, and how to convert color spaces.