Using Masks and Layers—Painting, Filling, and Color Tools - GIMP 2.6 for Photographers: Image Editing with Open Source Software - page 211

Creating a Gradient—the Gradient Select and
Gradient Editor Windows

Figure 3.35 shows the Tools palette, Blend tool settings and
Gradients window. The icons at the bottom of the Blend tool
settings are (A) Save options to…, (B) Restore options from…,
(C) Delete saved options, and (D) Reset to default values. The
options at the bottom of the Gradients window are (1) Edit
gradient, (2) New gradient, (3) Duplicate gradient, (4) Delete
gradient, and (5) Refresh gradients.
You may call up the prefabricated color gradients from
the Blend tool's options. If you want to edit a color gradient,
you will find them in the Layers, Channels, and Paths dock or
you may open the Gradients window by choosing Windows
> Dockable Dialogs > Gradients . Both ways offer you a set
of premade gradients. However, they are write-protected
and can't be manipulated. You have to duplicate the
gradient by right-clicking with the mouse in the Gradients
dialog box.
Double-clicking the default gradient blend (preset
foreground to background color), or clicking on the New
gradient button ( Figure 3.35 ) will cause the Gradient Editor
dialog to appear so that you can edit the gradient blend.
The Gradient Editor dialog displays the preselected
gradient blend (in this case, the default blend ranges from
black to white). Underneath the gradient blend, you'll notice
a gray slider with black arrows at the left and right margins
and a gray one in the center.
Right-click on the slider to open the context menu for
the Color Editor . In the context menu, click the left mouse
button on the Left Endpoint's Color option. Another pop-up
window, Load Left Color From , will appear. Select a color as
described earlier and click OK to accept your changes. The
color you selected should now appear at the left endpoint of
the color slider.
Repeat the steps to select a color for the right endpoint.
Because this exercise requires you to create a three-
color gradient blend, you'll need to right-click on the slider
underneath the blend in the Gradient Editor window to open
the context menu. Select the Split Segments at Midpoints
option.
The gradient blend is now split in the slider underneath
the gradient display, but it initially appears the same. Double-
click the left half of the slider to see how it works. You'll notice

Figure 3.35
Tools palette, Blend tool settings and Gradients window

Figure 3.36
The Gradient Editor