The blending mode controls how pixels in an image are affected by painting and editing tools. It’s helpful to think in terms of the following types of colors when visualizing a blending mode’s effect:
The base color is the original color in the image.
The blend color is the color being applied with the painting or editing tool.
The result color is the color resulting from the blend.
Throughout this lesson, you will learn how to specify a blending mode for a layer in the Layers palette and for a tool in the tool options bar.
For color illustrations of the different layer blending modes available in Photoshop ...