Image Processing Reference
In-Depth Information
Photoshop has full color management support, and it lets you select from four
different color spaces when converting a RAW file. Of the four, Adobe RGB (1998)
is the most commonly used color space, and it is an appropriate choice for general
image editing. ProPhoto RGB is a bit larger color space than Adobe RGB (1998),
and it is preferred by many pro shooters for the slightly wider color range possible.
sRGB IEC61966-1 is designed for screen display, such as web browsers or digital
slideshows. Unless you know in advance that your image conversion is only going to
be used for screen display, Adobe RGB (1998) or ProPhoto RGB will be the best
choices.
Note: Color management is the term given to the process of making sure that your image's color is con-
sistent from one device (such as the monitor) to another (such as your printer). Each of these devices uses
profiles to understand how to handle color. This is a topic unto itself and goes beyond the scope of this topic.
I highly recommend Color Confidence by Tim Grey (Sybex, 2004) for more in-depth information on color
management.
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Shadows and Highlights Clipping
Here's some advice: make life easier for yourself and turn on Shadows and Highlights
clipping by checking the boxes. When combined with the histogram, this is far and
away the best tool in Adobe Camera Raw to monitor exposure information in your
images. Without these two options enabled, you're just guessing at how much detail
you can pull from your photo.
As an example, I'll start with the image shown in Figure 2.13. I know that this
image has room for improvement in the shadows and highlights because the histogram
shows the image data ending before it reaches either end of the histogram.
Note: Clipping is the loss of image data, where highlights are completely white and shadows com-
pletely black. Generally, this is a bad thing.
To start with, I'll add more detail in the Shadows through the Shadows slider.
To increase shadow detail, move the slider to the right. As soon as I pass the maxi-
mum for the image, the preview shows information that is beyond the useable range
in bright blue (Figure 2.14). At this point, back off the shadow level until the blue
is gone.
Repeating the process for the highlights, I adjust the Exposure slider until I see
bright red (Figure 2.15). Again, back off the Exposure level until the red is gone.
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