What is a Photoshop overlay?

Related questions

1. Is Wood stronger with or against the grain?
2. What is the strongest wood in America?
3. What is the difference between soft wood and hard wood?
4. What is the softest wood?
5. What is 3d texture?
6. How is visual texture created?
7. What is Blinn in Maya?
8. What color is Maya?
9. What is three point lighting in Maya?
10. What does it mean to add texture to your hair?

Tags

1. #editing
2. #screens
3. #light
4. #multiplies
5. #photoshop
6. #areas
7. #overlay
8. #essential
9. #photo
10. #blend
11. #modes