The basic function of the mode is to increase the contrast drastically. Whenever I see pretty much dull image, I use this blend mode to make it more drastic. The best way is to duplicate the background layer and change the mode of duplicate layer to overlay. You can use Cmd+J/Ctrl+J as your keyboard shortcut for this.
This mode lightens the pixels that are lighter than neutral gray color and darkens the pixels that are darker than neutral gray. The result is pretty much high contrast image that sometimes looks like a wedding filter as shown in Fig. 6.13.
12: Soft Light
This mode works same as Overlay but the only difference is that it’s little bit subtle. Here you won’t see that the colors are washed out like overlay. Fig. 6.14 is a nice demonstration of that. In that image, Soft Light has increased the contrast of the image by making light color pixels lighter and dark color pixels darker, but the result doesn’t contain any washed out image like Fig. 6.13. The effect is somewhat similar to shining a diffused spotlight on the image.
13: Hard Light
Like the above two modes, this mode also multiplies the colors. The effect is somewhat similar to shining a hard spotlight on the image.
14: Vivid Light
It dodges and burns the colors by increasing or decreasing its contrast. So basically it increases or decreases contrast by two folds. The rest of work is same as overlay blend mode.
15: Linear Light
It works same as Vivid Light but rather than increasing or decreasing contrast additionally, it brightens or darkens the image.
16: Pin Light
This mode is usually used to decrease the contrast. According the Adobe “Pin Light replaces the colors, depending on the blend color. If the blend color (light source) is lighter than 50% gray, pixels darker than the blend color are replaced, and pixels lighter than the blend color do not change. If the blend color is darker than 50% gray, pixels lighter than the blend color are replaced, and pixels darker than the blend color do not change. This is useful for adding special effects to an image.”
17: Hard Mix
As the name is suggesting, this mode gives the hardest contrast than any other mode can provide. Fig. 7.7 is an example of that. According to Adobe “Adds the red, green and blue channel values of the blend color to the RGB values of the base color. If the resulting sum for a channel is 255 or greater, it receives a value of 255; if less than 255, a value of 0. Therefore, all blended pixels have red, green, and blue channel values of either 0 or 255. This changes all pixels to primary additive colors (red, green, or blue), white, or black.”