Field guide

Erasing objects versus cutting out a subject

Object removal and background removal use opposite masks. One reconstructs what should be behind a marked object; the other preserves that object and discards everything else.

Erase when the final image should remain a complete rectangle with plausible scene texture. The fill needs intact neighbouring pixels that resemble the hidden background.

Cut out when the subject will be placed elsewhere or exported with transparency. Edge accuracy then matters more than guessing the original background.

Hair, glass and soft shadows need fractional transparency in a cutout. Those same details may be safely removed in an erase if the surrounding background is simple.

Decide the intended next step before painting a mask. Inverting a rough erase mask rarely produces a professional subject matte because the two tasks require different boundary decisions.