The colors displayed in the slice panes are greyscale and represent the underlying density data values: highest density corresponds to white, lowest density are colored black, and in between areas are colored shades of grey.

It is possible to change the color range used. A color range that goes from blue to red, or one that uses rainbow colors can be used. To change the color range, click the Visualization Settings pane's Planes tab. Then select a color range by clicking one of the Color Planes By radio buttons—see Figure 2.7, item 10.

Figure 2.7. Options for controlling planes

Figure 2.8. Rainbow colormap

Choose the Rainbow colormap and notice the difference in the resulting images displayed in the slice plane as shown in Figure 2.8.

With the rainbow colormap it is easier to see small variations in the data, for example the variation in the center of the tooth root from blue to green. Using the greyscale colormap the whole center appears the same shade of grey.

With the greyscale colormap it is easier to tell what the underlying data values are. With the greyscale colormap you know that a dark grey region is substantially different than a white region. Using a rainbow colormap they show up as green and red, and it is not as obvious that green and red represent substantially different data values. It is also not as obvious that red represents a high data value, and the blue represents a low data value.