Adobe Photoshop CS5 for Photographers - Martin Evening [275]
Camera Raw profiling
As was explained in Chapter 3, Camera Raw uses data accumulated from two sets of profiles which have been produced using daylight balanced and tungsten balanced lighting. This method of profiling works really well with most normal color temperature settings, but the data gathered is based on a small sample of cameras (sometimes just one!) and cannot be regarded as offering absolute accuracy. It may be helpful to follow the calibration procedure (described in the same chapter) to obtain the most accurate colors.
Profiling the input
Input profiling is possible, but it's easier to do with a scanner than it is with a digital camera. To profile a scanner you'll need to scan a film or print target and use profile creation software such as X-Rite's ProfileMaker Pro™ program to read the data and build a custom profile based on readings taken from the scanned target (Figure 12.9). The target measurements are then used to build a profile that describes the characteristics of the scanner. This profile should be saved to the Macintosh Library/ColorSync/Profiles folder, or, on a PC, saved to the Windows/System32/Spool/Drivers/ Color folder. It can then be incorporated into your color managed workflow to describe the image data coming into Photoshop (refer back to Figure 12.6). This can be done by selecting the profile in the scanner software or by assigning the profile in Photoshop as the file is opened.
Figure 12.9 The ProfileMaker Pro™ interface.
Camera profiling is a lot trickier to do and few photographers feel this is something worth bothering with. This is because the camera sensor will respond differently under different lighting conditions and you would therefore need to build a new profile every time the light changed. This is not necessarily a problem if you are using a digital camera in a studio setup with a consistent strobe lighting setup. In these circumstances it is probably very desirable that you photograph a color checker chart and take measurements that can be used to create a custom input profile for the camera. For example, the X-Rite Eye-One Photo system offers a camera profiling option.
Overall, I would not stress too much about input profiles unless it is critical to your workflow that you have absolute color control from start to finish. For example, a museum photographer who is charged with photographing important works of art would absolutely want to profile their camera, but is it always necessary or desirable? In Figure 12.10 I suggest that the correct white balance and input profiling is sometimes irrelevant, as it is more important to trust what you see on your monitor display and obtain good color management between the image seen on the computer display and what you see in the print.
Figure 12.10 Here are three photographs taken on and around the London Eye ferris wheel. These pictures have each been processed using an incorrect white balance setting. In this situation, input color management becomes irrelevant and it matters more how consistent the appearance is between the computer display and the print output.
Profiling the output
Successful color management also relies on having accurate profiles for each type of media paper that's used with your printer. The printer you