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Pete
Bauer on Photoshop
Understanding Textures & Lighting, Part 2 of 2
Textures
and the Lighting Effects filter can make an image jump right off
the page or screen. Using a texture to create 3D, however, is a
scary thing for most Photoshop users. We'll take some of the mystery
out of the process.
In the
previous column we explored how the Lighting Effects filter works
with textures to create a 3D look. This time, we'll look at a couple
of ways to apply the filter to photographs.
The
easiest way to add texture with the Lighting Effects filter is to
use one of the image's existing channels to create a surface texture.
This results in an image that appears to have been painted onto
a surface. Figure 1 shows our test image, which can be found in
the Samples folder installed with Photoshop 6.

To
create a channel to use as a texture, simply drag one of the existing
color channels to the New Channel button at the bottom of the Channels
palette. (Remember that the composite channel called RGB is not
actually a channel, and so cannot be duplicated.)
Using
the menu command Filter> Render> Lighting Effects opens the dialog
box shown in Figure 2. Note that, at the bottom, Red Copy has been
chosen as the texture channel.

The
Result is shown in Figure 3.

Since
photographs already have shadows and highlights naturally, adding
them with the Lighting Effects filter is generally unnecessary.
The filter can, however, be used to emphasize them.
Duplicate
a channel to use as the texture, then roughly paint the highlights
and shadows you desire, as shown in Figure 4. Using the principles
explained in the previous column, white a will create highlights
and neutral gray represents no change.

This
creates a mask that can be viewed as an overlay by restoring the
visibility of the RGB composite channel. It will appear as a normal
Alpha channel (Figure 5).

To
prevent the filter from being applied too harshly, blur the rough
mask. In this case, I used the Magic Wand to select the background,
used the command Select> Inverse, and then applied a Gaussian Blur
of 5 pixels. The result is seen in Figure 6.

The
selection was maintained, applying the Lighting Effect to only the
foreground subject. Figure 7 shows the effect.

SIX
SHOOTERS
When installing Photoshop 6, you may need to swap CDs and insert
the disk from your previous version. Make sure to use the Eject button
in the Installer window. If it is grayed out, click once on the Photoshop
6 CD to select it. This has generated a very large column of requests
for assistance. The vote here is for Adobe to, in the future, go back
to simply typing in the old serial number.
Make sure that no other programs are running during installation,
especially your Web browser. Installers should always run alone, whether
on Mac or Windows, for best results. In this case, it's very important
that the Web browser be shut down to allow for proper installation
of the SVG Viewer plug-in. Additionally, this seems to cause some
problems with the installation of Adobe OnLine.
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