What is the difference between a Layer Mask and an Opacity Mask?

Both Layer Masks and Opacity Masks control the visibility of objects, but they work differently.

Feature Layer Mask Opacity Mask
Usage Primarily used in Photoshop, not native to Illustrator. Used in Illustrator to control transparency.
How It Works Uses black & white to hide or reveal parts of a layer. Uses gradients or grayscale to control object transparency.
Editing Editable with brushes and selections. Editable with gradients, vector shapes, and transparency.
Non-Destructive? Yes, can be adjusted anytime. Yes, can be adjusted anytime.
Where to Find? Available in Photoshop. Found in Transparency Panel (Window → Transparency).
Opacity Mask in Illustrator: How It Works :
  • A black area in an opacity mask makes objects fully transparent.
  • A white area keeps objects fully visible.
  • Grayscale/gradients create smooth fading effects.
Steps to Apply an Opacity Mask in Illustrator :
  1. Create an object (e.g., a rectangle).
  2. Place a grayscale gradient or shape on top.
  3. Open Transparency Panel (Window → Transparency).
  4. Select both objects and click “Make Mask”.