86
Real World Camera Raw with Adobe Photoshop CS2
The Detail Tab
The sliders in the Detail tab (press Command-Option-2) let you apply global
sharpening and reduce noise in both luminance and color (see Figure 4-28).
To see the effect of these controls, you need to zoom the preview to at least
100%—often 200% or higher is more useful—because while the Camera
Raw preview tries to show their effect at 50% or higher zoom, they’re hard
to see until you zoom in. The up and down arrow keys move the sliders in
increments of 1. Adding Shift moves the sliders in increments of 10.
Most cameras need some amount of color noise reduction regardless
of ISO speed. Each camera vendor makes its own compromise between
image softness and color artifacting—if an image detail falls on only a red,
only a green, or only a blue pixel, the demosaicing algorithm has to make
some guesses to fi gure out what color the resulting image pixel should
really be, and sometimes single-pixel color artifacts result. Color noise
reduction can also eliminate rainbow artifacts in highlights and green-
magenta splotches in neutral grays. The need for luminance noise reduc-
tion, though, is more dependent on ISO speed and image content.
Sharpness. The Sharpness slider lets you apply a variant of Unsharp Mask
to the preview image or to both the preview and the converted image,
depending on how you set Camera Raw Preferences (see The Camera
Raw Menu,” earlier in this chapter). Unlike Unsharp Mask, Camera Raw’s
Sharpness only offers a single control—the Threshold value is calculated
automatically based on the camera model, ISO, and exposure compensa-
tion values reported in the images metadata.
Figure 4-28
The Detail tab
Chapter 4: Camera Raw Controls
87
I fi nd the Sharpness control a bit of a blunt instrument. I usually set the
preference so that Sharpness only applies to the preview, and apply more
controlled sharpening post-conversion in Photoshop. But if I’m simply
trying to get a bunch of images processed for approval, trying to make
them good rather than great, I may apply a quick sharpen here, knowing
that I can reprocess the “hero” shots from the raw fi le with no sharpening
once I know which ones they are.
Luminance Smoothing. The Luminance Smoothing slider lets you con-
trol grayscale noise that makes the image appear grainy—its typically a
problem when shooting at high ISO speeds. The default setting is zero,
which provides no smoothing; but many cameras benefi t from a small
amount—say 2 to 4—of luminance smoothing even at slow speeds, so you
may want to experiment to fi nd a good default for your camera. At high
ISO speeds—800 and up— you’ll almost certainly need to apply luminance
smoothing at much higher settings.
At very high settings, the Luminance Smoothing slider produces images
that look like they’ve been hit with the Median fi lter, so always check the
entire image at 100% view or above before committing to a setting.
Bear in mind that the controls in the Adjust tab can have a huge impact
on the visibility of noise. Unlike many raw converters, Camera Raw gives
you access to everything the camera has captured, including, sometimes,
extremely noisy shadows that other converters may simply map to black.
Attempting to pull shadow detail out of an underexposed image will almost
certainly result in noisy shadows.
Color Noise Reduction. Color noise manifests itself as random speckles
of color rather than gray, and in my experience, all cameras need some
amount of color noise reduction. While the visibility of color noise varies
with ISO speed, the required correction seems to vary much less than
that that required for luminance noise, so you can generally fi nd a good
default value for your camera and deviate from it only when you see an
obvious problem.
Its diffi cult to show typical noise scenarios in print (bear in mind that
noise that looks objectionable on the displayed RGB fi le is often quite
invisible by the time the image has been converted to CMYK and printed),
so Figure 4-29 shows something close to a worst-case scenario—ISO 1600
with sodium-vapor lighting!
88
Real World Camera Raw with Adobe Photoshop CS2
Figure 4-29
Noise reduction
The image at 200% view
(right), and the entire
image (below)
Color Noise Reduction
set to 15 removes the
color noise.
Luminance Smoothing
set to 40 greatly reduces
the luminance noise
(higher settings softened
the image wthout
signifi cantly helping
the noise).

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