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The tone-mapping controls work together to let you tailor Camera Raw’s conversion from linear capture to gamma-encoded output. Collectively, they have a huge influence on the overall tonality of the image. Even if you plan to do significant postconversion editing in Photoshop, it’s well worth using Camera Raw’s tone-mapping features to get the image as close to the desired end result as possible.

Why? Because doing so produces a gamma-encoded image in Photoshop with the bits already distributed optimally. That means that the image will better withstand subsequent editing (see “Losing Data and Limiting Options,” earlier in this chapter) and you have less work to do after the con-version in Photoshop.

The adjustments made by Exposure, Blacks, Brightness, Contrast, and the Tone Curve tab are applied as a single operation on the raw conversion, so the order in which you make the adjustments doesn’t matter from a quality standpoint. We’ll discuss the workflow reasons for making adjustments in a specific order in Chapter 5, Hands-On Camera Raw.

Exposure. The Exposure slider is really a white-clipping control, even though it affects the whole tonal range. You can achieve superficially similar results using Exposure or Brightness, but even though Brightness values greater than 100 can produce white clipping, Brightness is at heart a mid-tone adjustment.

At positive values, the Exposure slider behaves very much like the white input slider in Photoshop’s Levels command or the Exposure slider in Photoshop’s Exposure command, clipping levels to white. But since it’s operating on linear data, it’s gentler on the midtones and shadows than white clipping in Photoshop on a gamma-corrected image, and it offers finer control over the white clipping than do Photoshop’s controls.

When you set the Exposure slider to negative values and/or add Recovery, the story is very different, because one of Camera Raw’s most remarkable features comes into play. Unlike most raw converters (or Photoshop’s Exposure command), Camera Raw offers “highlight recovery.” Most raw converters treat all pixels where one channel has clipped highlights as white, since they lack complete color information, but Camera Raw can recover a surprising amount of highlight detail from even a single channel. It does, however, maintain pure white (that is, clipped in all channels) pixels as white (unlike

ptg most converters, which turn clipped pixels gray), and darkens the rest of the

image using special algorithms to maintain the nonwhite pixels’ color. See the sidebar “How Much Highlight Detail Can I Recover?” for more techni-cal details, and see Figure 2-12 for a real-world example.

It’s simply impossible to match Camera Raw’s highlight detail recovery in Photoshop on a gamma-corrected image. In linear space, half of the captured data describes the brightest f-stop, so you have a large number of bits describing the highlights. Once the image is converted to a gamma-corrected space, you have far fewer highlight bits to play with.

Blacks. The Blacks slider is the black clipping control. It behaves very much like the black input slider in Photoshop’s Levels command, but its effect tends to be a little more dramatic, simply because it’s operating on linear-gamma data, which devotes very few bits to the deepest shadows. In the first edi-tion of this book, Bruce characterized the Blacks control as “a bit of a blunt instrument,” but changes to the logic in Camera Raw 2.3 and later have made it a much more sensitive tool. We now use it fearlessly to set the black point.

Fill Light. After adjusting the Blacks setting, check out the usefulness of Fill Light settings for your image. Fill Light is an adaptive shadow adjust-ment tool that uses a mask-based factor to lighten deep shadows. It’s similar to Photoshop’s Shadow/Highlight adjustment but arguably better since it’s working in linear gamma.

Brightness and Contrast. The Brightness and Contrast controls let you tweak the conversion of the intermediate tones from the linear capture to the gamma-corrected output space. They work completely differently from the similarly named Photoshop Contrast and Brightness controls. Instead, they behave similarly to Photoshop’s Levels and Curves, respectively (Brightness is a midtone adjustment, Contrast is an S-curve) but with one important difference: the Camera Raw controls use an algorithm that preserves the original hue, whereas hard curve adjustments to the composite RGB curve in Photoshop can cause slight hue shifts. While not a pure lumi-nance curve, the saturation is designed to mimic the saturation effects found in film when contrast is increased.

If you make little or no adjustment with the Exposure slider, it’s advantageous to use Camera Raw’s Brightness and Contrast sliders and Tone Curves rather than using Photoshop’s tools. But with bigger Exposure adjustments, it becomes even more essential that you make complementary Brightness and Contrast moves in Camera Raw (see Figures 2-5 and 2-6, earlier in this chapter).

TIP Check clipping at 100% view. At zoomed-out views, you may wind up clipping pixels you didn’t intend to. Always check the 100% view before doing the conversion to make sure that you aren’t clipping pixels you wanted to preserve.

ptg Figure 2-12 Highlight recovery.

We suppose that everybody would consider this image as being overexposed, as indicated by the white spike at the right end of the histogram and the clipping warning shown in red in areas of the image. This is Expose To The Right in the extreme.

Simply selecting Auto in the Basic panel will reduce the Exposure and add highlight recov-ery. Notice the amount of the red clipping indicators has been greatly reduced. However, the image still looks very light and washed out so additional work is needed.

Here the Blacks setting has been moved to the maximum of +100 and Highlight Recovery to +43. Brightness has been reduced consider-ably to –113. With the addition of Clarity, Vibrance, and Saturation, the image’s tone curve has been optimized. Notice also that the white balance has been cooled down to 5450°K. What you can’t see (and will be shown in Chapter 5, Hands-On Camera Raw) is the amount of local tone and color correction that is also being used. Clearly this image is severely overexposed, but Camera Raw can still be used to get something out of what might otherwise be presumed as nothing.

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