Refine your Layer Masks
Photoshop’s Refine Mask controls can help you to accurately mask objects that have lots of fine detail such as hair.
After creating and roughly painting in the mask, right-click the mask in the Layers panel and select the Refine Mask option.
Put a tick in the Smart Radius box to tell Photoshop to select the radius for you, and paint in the mask along the edges of the object.
If necessary, set the Radius yourself using a small radius (1 or 2 pixels) for areas with a clean edge, or a large Radius where there’s lots of fine detail breaking into the background.
It’s also helpful to select the Decontaminate Colors option because this will remove any overspill of background colour onto the subject.
The controls in the Adjust Edge section enable you to tweak the mask, smoothing out jaggy areas, feathering the edge and increasing the contrast to add partially selected (grey) areas.
The Shift Edge control expands or contracts the mask depending on whether a negative or positive figure is used.
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