#25. Using Symbol Color Effects
Let’s say you want to change the color of an individual instance of a symbol. You can’t use the Color panel to change its stroke or fill, because a symbol instance isn’t editable. You can’t double-click the instance and change its color in symbol-editing mode, because doing so would change the color of all instances of that symbol.
The solution is to select the instance and look on the Properties panel for a section labeled Color Effect. Below that label is the Style menu, from which you can choose the type of effect you want to apply. Depending on which option you select, a different control (or set of controls) will appear next to the menu. The available options are:
- Brightness. The brightness control is a slider ranging from –100% to 100%, with 0% as the default. Choosing a positive number brightens the instance; choosing a negative number darkens it.
- Tint. There are several tint controls. The first, to the right of the Style menu, is a standard color menu that allows you to choose a tint for the instance in the same way you’d ordinarily choose a color for a stroke or fill (see #8). Farther down are three sliders—labeled Red, Green, and Blue—that allow you to adjust the level of each primary color on a scale ranging from 0 to 255.
None of these tint controls discriminates between strokes and fills. As a result, tinting an instance causes the stroke and fill to appear exactly the same color, even if they had contrasting colors to begin with.
To avoid this problem, you can use the Tint slider. This control acts as if the tint were a separate object overlaying the instance: If the slider is set to 100%, only the tint is visible; if the slider is set to 0%, only the unchanged instance is visible. At intermediate settings—such as 50%, the default—the tint is treated as if it’s partly transparent, allowing some of the underlying instance to show through. As you lower the tint amount, the original contrast between the stroke and fill colors becomes more apparent, but the tint looks increasingly washed out (Figure 25a).
Figure 25a The effects of the Tint slider can be seen in these three different views of the same instance. On the left, the tint is set to 0%, leaving the original instance unchanged. In the center, the tint is set to 100%, completely covering the instance with a uniform color. On the right, the tint is set to 50%, allowing the instance to partially show through the tint.
- Alpha. Alpha is synonymous with opacity. When the Alpha slider is set to 100% (the default), the instance is completely opaque; when it’s set to 0%, the instance is completely transparent (invisible). If the background behind the instance is white, the effect of lowering the alpha is indistinguishable from that of raising the brightness.
Advanced. This option lets you control tint and alpha at the same time. There are four controls—one each for Alpha, Red, Green, and Blue—with settings that align in columns (Figure 25b). By changing the values in the left column, you can vary the amount of alpha and of each primary color by percentage. (Note that a setting of 100% in this column indicates the level of alpha or color that’s already in the instance. For example, if the instance originally contains 30 percent blue, a setting of 100% would maintain that level of blue; a setting of 50% would bring it down to 15 percent blue.)
Figure 25b The Advanced option allows you to change alpha and colors by percentages or by absolute amounts.
By changing the values in the right column, you can add or subtract absolute amounts of alpha, red, green, and blue, in increments ranging from 255 to –255. Because these controls apply their calculations individually to each color in the instance, they preserve the differences between stroke and fill colors. Therefore, if you wish to apply a color effect to an instance, you’ll usually get better results with the Advanced option than you would with the Tint option.