The Lasso selection tool enables you to easily make detailed selections. Simply sketch a lasso around an object in the scene and Exposure will select it for you.
Photo: Andrea Livieri
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The selection tools are flexible enough to use however you’d like, but the first tool you use to create the initial selection will set up the workflow for adjusting it. Each of the selection tools do the same thing in a different way to give you control over various content.
Making Lasso Selections
The Lasso selection tool is perfect for objects that are clearly defined. Simply use the Lasso to trace around the object in the photo and Exposure will generate a selection for you. The shape you draw tells Exposure where to look for the edges of the object you wish to select. The selection that the Lasso tool creates is a detailed, adjustable polygon.
Refining selections
The Sensitivity slider adjusts how Exposure generates the lasso selection. Higher amounts of sensitivity make Exposure look for harder, more defined edges when it creates the selection. Low sensitivity will include more detail and less variation in the selection edge.
If you want to remake the lasso you made, press the Clear button. On the other side of the panel, press Commit to accept the selection on the screen. This converts the lasso selection into a polygon. In the panel, notice the active selection boundary is labeled as an Include Polygon.
Refine the selection boundary with the border points. You can move points, or delete unneeded points easily to make the edges of the selection match even better with those in the image.
The thickness of the selection boundary can be adjusted because it is now a polygon. The Base Width slider controls the size of the area Exposure searches when locating the object’s edges. A narrower base width will give Exposure accurate data about the edge location, but it will take more time to position each point precisely.
For more control, select a point or several points along the edge and use the Relative Width slider to change each segment independently. You can easily change the relative width with the mouse wheel and the modifier key Shift. Simply hover over a point, or several selected points in the preview and then scroll to change the point width.
Using masks
The layer masks created with the Lasso tool enable you to easily control different zones within the photograph to apply editing adjustments. When using strong adjustments, like 2 or more stops of Exposure, the precision of the selection boundary becomes much more important. In this scenario, use the Edge Options controls to modify the selection.
The Expand slider will widen or shrink the selection boundary. The Matting slider makes edge-sensitive expansion. It pushes the mask out toward the border of the selection to blend away thin lines that may appear at the edges of the mask.
