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To compress selected areas of a JPEG:
1.
In Original view, select an area of the graphic for compression using one of the Marquee
tools.
2.
Select Modify > Selective JPEG > Save Selection as JPEG Mask.
3.
Select JPEG from the Export File Format pop-up menu in the Optimize panel, if it's not
already selected.
4.
Click the Edit Selective Quality Options button in the Optimize panel.
The Selective JPEG Settings dialog box opens.
5.
Select Enable Selective Quality and enter a value in the text box.
Entering a low value compresses the Selective JPEG area more than the rest of the image.
Entering a high value compresses the Selective JPEG area less than the rest of the image.
6.
Change the Overlay Color for the Selective JPEG area if desired. This does not affect
the output.
7.
Select Preserve Text Quality. All text items will automatically be exported at a higher level,
regardless of the Selective Quality value.
8.
Select Preserve Button Quality. All button symbols will automatically be exported at a
higher level.
9.
Click OK.
To modify the selective JPEG compression area:
1.
Select Modify > Selective JPEG > Restore JPEG Mask as Selection.
The selection is highlighted.
2.
Use the Marquee tool or another selection tool to make changes to the size of the area.
3.
Select Modify > Selective JPEG > Save Selection as JPEG Mask.
4.
Change selective quality settings in the Optimize panel if desired.
To undo a selection, select Modify > Selective JPEG > Remove JPEG Mask.
Blurring or sharpening detail
You can set Smoothing in the Optimize panel to help decrease the file size of JPEGs.
Smoothing blurs hard edges, which do not compress well in JPEGs. Higher numbers produce
more blurring in the exported or saved JPEG, typically creating smaller files. A smoothing
setting of about 3 reduces the size of the image while still maintaining reasonable quality.
348 Chapter 14: Optimizing and Exporting
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