Image Processing Reference
In the Change Foreground Color window, there are tabs allowing you to
change the way in which color is represented. The most common is RGB mode
(and HSV mode), which is set as default, resembled by the tab showing the
GIMP icon. This color mode is found in most popular image editing programs.
The other color models are CMYK colors (four-color printing), color
triangle, and watercolors (additive mixing colors).
Probably the most striking field is the square field on the left side,
showing the hue of one chosen color. Clicking into this field lets you select
the lightness levels for a color. Just click the desired hue to activate it. It will be
shown as a new color in the Current field
To the right of this field you find the RGB spectrum, if the radio button
next to H is enabled. Click into this field or shift the mouse on it while holding
the left mouse button down to preselect a color.
• Radio buttons The H radio button should be enabled for the default
color display (see figure 3.31 ). The other radio buttons activate different
views of the Hue field for selection.
• Sliders : You can move the H (for Hue ) slider to produce alternative colors
with the same lightness, using the settings in the figure. In general, the
sliders serve to mix colors; an alternative for mixing colors is to select a
color (or color range) with the mouse, as described earlier.
• Numerical entries : You can also type decimal values for R ed, G reen and
B lue to set or mix a color. Optionally, in the HTML notation field, you can
enter a 6-character hexadecimal value to set a specific color. This works
well when you want to import an exact color from another program.
• Buttons : The OK button adds the selected color to the Toolbox and
closes the Change Foreground Color dialog. The Reset button rejects the
selected color and lets you select another color. The Cancel button closes
the dialog without accepting the color you selected as the foreground or
The Bucket Fill Tool
Getting back to the exercise, let's say you now want to insert a single-color
sky. To achieve that goal, you will first need to fill a separate layer with color;
this layer will be seen as the sky when viewed through the transparent areas
of the landscape layer above it. The Bucket Fill tool will be used for this.
The Bucket Fill tool also has its own tool options (double-click the tool
icon in the Toolbox).
You don't need to change any options. The important settings for now, FG
color ill and Fill transparent areas , are preselected by default. Once you select
the desired foreground color and activate the appropriate layer in the Layers
dialog, just click the tool on your image. The layer will be automatically filled
with the selected color.
The tool options dialog for the
Bucket Fill tool