The pencil, ellipsis, rectangle and line tools create pencil lines. Pencil lines are defined by a central vector line to which Harmony adds thickness.
Pencil lines tend to obscure the actual edges of the shape they are around. Sometimes, knowing the actual edge of shapes surrounded by pencil lines can be useful. To work around this problem, it is possible to temporarily adjust the opacity of pencil lines in the Camera view.
This will only affect the way your pencil lines are displayed in the OpenGL preview of the Camera view. The rendered image will not be affected.
Outlines created with the Brush tool are not pencil lines. They are fully defined vector shapes. Hence, this feature will not work on brush strokes.
In either the Drawing view or Camera view toolbar, click on the Top Light icon. The Pencil Lines Opacity feature can also be accessed through the Preferences panel—see Drawing Preferences.
The Onion Skin and Light Table Transparency dialog opens.
In the Onion Skin and Light Table Transparency dialog box, use the Pencil Lines Opacity slider to globally increase or decrease the opacity of central vector lines. Sliding the slider all the way to the right equals 100% opacity. Sliding the slider all the way to the left equals 0% opacity.