Image Processing Reference
3.6 Touchup Work 5—Freshening Up a
3.6.1 Steps Involved and Description of Work
The exercise discussed in this section involves the following steps:
• Working with selections or masks
• Working with layers
• Working with the FG/BG dialog (foreground and background color) and
the Change Foreground Color window
• Working with the Gradient tool and the Gradient Editor
In the image dullsky.png , we will replace the existing blue-gray sky with
a color fill or color gradient on a new layer. To this end, you will use the Fuzzy
Select tool (Magic Wand) to select and delete the existing sky. The layer with
the color fill underneath it will then appear through the transparent area of
the next higher layer, the one with the landscape.
3.6.2 Step 1: Selecting an Area by Color,
Deleting It, and Replacing It by Color Fill
Follow these steps to begin:
• Open the image dullsky.png in the SampleImages folder on the DVD.
• Save it in your exercise folder as bluesky.xcf . The XCF file format is required
to save the layers in the image.
• Run a tonality correction ( Colors > Levels ) and freshen up the image's
colors by using the options from the Colors > Hue-Saturation or Color
Balance menu item.
• Access the Layers, Channels, and Paths dialog for the image from the
Windows > Dockable Dialogs menu. Click the Create a New Layer button to
create a new layer. Save it as Sky .
• Duplicate the Background layer (the one with the landscape) by right-
clicking on the layer in the Layers dialog and selecting Duplicate Layer .
Save it as Landscape . Make the Background layer invisible. Add an alpha
channel to the duplicated layer, as the transparency feature is not
available in duplicated backgrounds (see the context menu).
• Use the Fuzzy Select tool and click on the color of the sky to select it.
Another method would be to apply the Select by Color tool . Be sure to
set the landscape layer to active in the Layers dialog. By clicking in the