94 Technical Issues: Killing the Gremlins
a rainbow pattern effect and can be quite diffi cult to deal with. But
deal with it you must before submission.
Most digital cameras are fi tted with an antialiasing (AA) fi lter to
reduce moiré effects. This works by slightly softening the image. The
downside is a slight loss of resolution. A few cameras take a chance
on moiré and do not use an AA fi lter. This results in a sharper image,
but it leaves you spending more time in postprocessing removing not
just moiré but other forms of color noise.
Figure 5.13 illustrates a small part of an image opened up in
Photoshop with pretty bad moiré. Figure 5.14 shows the image being
worked on to remove the moiré, using a simple solution that is usually
good for the job. Here is what you can do:- In Photoshop, select the Paint Brush and then from the Mode menu, choose
Color. - Choose the eyedropper tool, and select a part of the image that is closest to the
average color. In this case, it’s a bronzy pink shade.
FIGURE 5.13 Moiré sample.