About Blend Modes                   

Blend mode

Result

Normal

Displays pixels of underlying layers based on the opacity of pixels on the selected layer. If data is fully opaque, no pixels show through.
As the opacity decreases, more pixels from underlying layers show through.

Darken

Displays pixels in the selected layer that are darker than the underlying layers.
Pixels lighter than the underlying layers disappear.

Lighten

Displays pixels in the selected layer that are lighter than the underlying layers.
Pixels darker than the underlying layers disappear.

Hue

Applies the hue of the selected layer (without changing the saturation or lightness)

Hue
(Legacy)

This blend mode was first introduced in version 5 of PSP, and functions similarly to the hue blend mode.
It's retained for the sake of compability with older versions of PSP

Saturation

Applies the saturation of the selected layer to the underlying layers (without effecting the the hue or lightness)
This blend mode was introduced in PSP 8, and is an improvement on the original Hue bland mode (Saturation legacy)

Saturation
(lagacy)

This Blend mode was first introduced in PSP 5, and functions similarly to the saturation blend mode.
It is retained for the sake of compability with the older versions of PSP.

Color

Applies the Hue and saturation of the selected layer to the underlying layers (without effecting the lightness)
This blend mode was introduced in PSP 8 and is an improvement on the original Color Blend mode

Luminance

Applies the luminance (or lightness) of the selected layer to the underlying layers, without affecting the hue of saturation

Multiply

Combines the colors of the selected layer with the underlying layers to produce a darker color.
Multiplying any color with black produces black.
Multiplying any color with white leaves the color unchanged,

Screen

Lightens the color of underlying layer by multiplying the inverse of the selected and underlying layers.
The result is a color that is the same or a lightened version of the selected layer.

Dissolve

Randomly replace the color of some pixels on the selected layer with those of the underlying layers to create a speckled effect.
The selected layer's opacity determines the number of pixels replaced.
The lower the opacity, the more pixels that are replaced.

Overlay

Combines the Multiply and Screen Blend Modes.
If the color channel value of underlying layers is less than half the maximum value, the multiply blend mode is used.
If the color channel value is greater than or equal to half the value, the Screen Bland Mode is used.
The Overlay blend mode shows patterns or colors of the selected layer while preserving the shadows and highlights of underlying layers.

Hard light

Combines the Multiple and Screen blend modes.
If the color channel value of the selected layer is less than 128, the Multiple blend mode is used.
If the color channel value is greater than or equal to 128, than the Screen blend mode is used.
In general, use the Hard Light blend mode to add highlights or shadows.

Soft Light

Combines the Burn and Dodges blend modes.
If the color channel value of the selected layer is less than 128, the Burn blend mode is used.
If the color channel value is greater than or equal to 128, the Dodge blend mode is used.
In general, use the soft light blend mode to add soft highlights or shadows.

Difference

Subtracts the selected layer's color from the color of the underlying layers.

Dodge

Lightens the image by having the lightness value of the colors in the selected layer lighten the colors of the underlying layers.
Light colors produce the most lightening, black has no effect.

Burn

Darkens the image by having the lightness values of the selected layer reduce the lightness of underlying layers.

Exclusion

Creates an effect similar to, but softer then the Difference blend mode.