Shaders and Texturing - An Introduction to Computer Graphics for Artists - page 197

textures. On the other side of the debate are artists who prefer to paint their textures.
These artists object to the various types of information pollution that occur in photo
textures, and prefer to paint their textures from scratch to prevent clogging any one
channel with information from another.
Both methods have their strengths and weaknesses. It is unquestionably more
work to paint a complex texture by hand than to photograph it. A photograph would,
however, be highly prone to contain unwanted information. This is why using a
combination of the two methods is not uncommon. A combined workfl ow requires
a source photo that is fi rst cleaned, and then used as reference for painting.
Sometimes a completely new image is made, other times the photo is retouched to
clean up the most obvious problems. For artists that require only the cleanest maps,
there is no substitute for making them by hand. If time is an issue and extremely
complex maps are needed, photos can work very well. If you are making The
Incredibles , you will probably want to paint your maps, but for visual effects in a
live action movie, a good argument can be made for using photos.

11.5.4 Painted Maps

The kind of skills associated with painting pictures are less closely related to the art
of painting texture maps than the skills related to decorative faux fi nish painting.
Faux fi nish painting is a method for imitating materials like wood or marble by paint-
ing patterns that resemble them. If an artist is to paint texture maps, it is important to
be sensitive to color so that they can match colors when needed and to be able to
design appealing color schemes. These are not the same skill, though they are related.
This is because the less skilled an artist is at matching colors, the smaller their color
vocabulary is and this limits the range of choices when designing color schemes.
Painted maps have the advantage that they are naturally free of noise and color
distortion unless it is purposely introduced. If painted well, they will also be free of
all of the problems introduced as artifacts of the photographic process (Fig. 11.18 ).
The diffi culty of painting maps is to include suffi cient convincing detail and to
select the optimal palette.

11.5.4.1 Palette

When painting texture maps it is a good idea to fi rst establish the palette that will be
used. A palette is a group of the major colors that will be used in the map, with the
exceptions of colors created by digital painting tools during the process of painting,
such as anti-aliasing between adjacent color areas or blending of semi-transparent
paint with lower layers of colors.
Colors used for textures can be thought of as swatches . A swatch is a color
sample . The swatch should be thought of as a pure version of the color, uninfl u-
enced by lighting and other effects (Fig. 11.19 ). As an example, a photograph of a