Microstock Photography

88 Technical Issues: Killing the Gremlins

use exposure compensation to increase exposure, so a good workfl ow

might be as follows:

• Select a low ISO setting, where possible. Make sure, though, that you have a high
  enough shutter speed to avoid camera shake. (You could try a wider aperture to
  achieve this.)


• Compose and take your shot; check the histogram.


• If the histogram shows problems, adjust the exposure to get the best histogram and
  then reshoot.


• If you are in any doubt, bracket your exposures; that is, take several versions of the
  same image at different exposures and choose the best later.

COLOR BLOTCHES

Another sort of noise is color noise that can look like uneven blotches,

as seen in the next image where an attempt has been made to extract

shadow detail from a church interior shot (Figure 5.8). Provided noise

in luminance or color forms is not too extreme, you can zap it in a

number of ways.

NOISE-REDUCTION SOFTWARE

The simplest solution for noise is to use a good specialized noise-

reduction software package like Neat Image (www.neatimage.com) or

Noise Ninja (www.picturecode.com). These products work by measur-

ing image noise through samples taken from within the image and

AB

FIGURE 5.8A and B Before (A) and after
(B) fi ltration of an image with blotchy color
noise.