Real World Adobe Photoshop CS2: Industrial-strength Production Techniques

At the bottom of the Camera Raw dialog box, four controls let you set output parameters for the converted image (see Figure 11-18). The settings you make with these controls apply to the current image, or to all the images being converted in a batch process. Unlike the settings made with the image-specific controls, these settings aren't saved with images. This is useful, because you can set the workflow controls to produce large files in a large-gamut color space for print or final delivery, or change them to produce small files in sRGB for review on the Web or e-mail.

Figure 11-18. Camera Raw workflow settings

Space lets you choose the destination color space for the conversion from one of four preset working spaces: Adobe RGB (1998), Colormatch RGB, ProPhoto RGB, or sRGB IEC61966-1 (the last being the "standard" flavor of the sRGB standard). See the sidebar "Camera Raw and Color" for details on how Camera Raw handles the color management aspect of the conversion.

Camera Raw and Color

One of the more controversial aspects of Camera Raw is its color-handling, specifically the fact that Camera Raw has no facility for applying custom camera profiles. Having tried most camera profiling software, and having experienced varying degrees of disappointment, we've concluded that unless you're shooting in the studio with controlled lighting and a custom white balance for that lighting, camera profiling is an exercise in frustration if not futility. So we've come to view Camera Raw's incompatibility with custom camera profiles as a feature rather than a limitation.

The way Camera Raw handles color is ingenious and, thus far, unique. For each supported camera, Thomas Knoll, Camera Raw's creator, has created not one but two profiles: one built from a target shot under a D65 (daylight) light source, the other built from the same target shot under an Illuminant A (tungsten) light source. The correct profiles for each camera are applied automatically in producing the colorimetric interpretation of the raw image. Camera Raw's White Balance (Color Temperature and Tint) sliders let you interpolate between, or even extrapolate beyond, the two built-in profiles.

For cameras that write a readable white balance tag, that white balance is used as the "As Shot" setting for the image; for those that don't, Camera Raw makes highly educated guesses. Either way, you can override the initial settings to produce the white balance you desire.

It's true that the built-in profiles are "generic" profiles for the camera model. Some cameras exhibit more unit-to-unit variation than others, and if your camera differs substantially from the unit used to create the profiles for the camera model, the default color in Camera Raw may be a little off. So the Calibrate controls let you tweak the conversion from the built-in profiles to optimize the color for your specific camera. This is a much simpler, and arguably more effective, process in most situations than custom camera profile creation.

Depth lets you choose whether to produce an 8-bit/channel image or a 16-bit/channel one. A 16-bit/channel file needs twice as much storage space as an 8-bit/channel one, but it provides 128 times as many tonal steps between black and white, so it offers much more editing headroom.

Size lets you resample the image on the fly, or convert it at the native camera resolution. The actual sizes offered depend on the camera from which the image came, but they generally correspond to the native resolution; downsampling to 66 percent or to 50 percent; and upsampling to 133 percent, 166 percent, and 200 percent.

Resolution lets you specify a resolution for the converted image, in pixels per inch or pixels per centimeter, giving you the option to save yourself a trip to the Image Size dialog box once the image is converted. Unlike the Size control, it has no effect on the number of pixels in the converted image.

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