by Julieanne Kost

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Created

November 10, 2010

The third group of Blend modes have a neutral color of black. This means that black as a blend color will have no effect on the result color. These blend modes all have stronger effects as the blend color becomes lighter. Using the Fill slider on Layers palette and using blend modes from this group may modulate this effect rather than performing a simple opacity blend the way normal mode does. The lightening modes are essentially the inverses of the darkening modes.

• Lighten – Looks at the color information in each channel and selects the lighter of the base or blend color as the result color. Pixels darker than the blend color are replaced, and pixels lighter than the blend color do not change.

• Screen – Looks at each channel’s color information and multiplies the inverse of the blend and base colors. The result color is always a lighter color. The effect is similar to projecting multiple photographic slides onto the same screen. Screen reduces contrast and can produce and effect similar to painting an area with bleach.

• Color Dodge – Looks at the color information in each channel and brightens the base color to reflect the blend color by decreasing the contrast. Color Dodge is an exception to the neutral color rule in this group – it is the only lightening mode that preserves blacks. Color Dodge is similar to moving the input white triangle in Levels. As such, color dodge increases contrast but may clip the brighter portions of the lower colors to white.

• Linear Dodge – Looks at the color information in each channel and brightens the base color to reflect the blend color by increasing the brightness.  Linear dodge is the combination of color dodge and screen. As such, it has a stronger lightening effect than either of them. Linear Dodge will clip bright values, unlike Screen.

• Lighter Color Compares the total of all channel values for the blend and base color and displays the higher value color. Lighter Color does not produce a third color, which can result from the Lighten blend, because it chooses the highest channel values from both the base and blend color to create the result color.

The first

The first image illustrates the leaf layer with it's blend mode set to Lighten. The second illustration shows the result of Screen, then Color Dodge, Linear Dodge (Add) and finally, Lighter Color.

One common use of the Screen Blend mode is to build up or reduce density in an image. To lighten a very dense image like the boy on the left, add a levels or curves adjustment layer, but don’t make any changes in the Adjustment panel. There won’t be any visible change at first, but changing the blend mode of the adjustment layer (in the Layers panel) to Screen will lighten the density of the image. You can also try soft light for a more subtle effect (but again, I'm getting ahead of myself). If you need to lighten the image even more, you can duplicate the adjustment layer. If the image lightens too much, decrease the opacity of the adjustment layer or paint in the adjustment layer's mask to selectively hide the adjustment. If you’re image is too light (like the girl on the right, you can follow the same steps found above to add an adjustment layer, but set it's blend mode to Multiply to increase the density.