Advanced Blending Techniques in Photoshop

By Jason Cranford Teague

Dateline: April 28, 2006
Version: Photoshop 7

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Most users are familiar with the general layer blending options such as Opacity and modes like Multiply and Overlay. However, deeper in Photoshop are advanced blending options that make those general effects look like a box of cheap crayons. Try these tips to simulate double-exposure photography.
Finding the Options
If nothing else, the Layer Style Blending Options dialog box is extremely accessible. After selecting the layer you want to blend, you can do any of the following:
  • Double-click the layer.
  • Choose Layer > Layer Style > Blending Options.
  • Choose Blending Options from the Layers palette menu.
  • Control/Right-click a layer, and choose Blending Options.
  • Click the Add a layer style icon at the bottom of the Layers palette, and choose Blending Options.
Surfing the Color Channels
Try using channels to blend two layers. Double-click your top layer to open the Layer Style Blending Options dialog box. Deselect a Channel and you will take away the visibility of that color channel in the layer. You also simultaneously blend the same color channel from the underlying layer with the top layer’s remaining visible channels. In other words, whatever color you deselect (and take away) from your top layer becomes the color from the underlying layer that is blended with your top layer. It’s confusing, but it’s also fun to experiment with! In the example, the Yellow channel of the man layer was deselected, so the yellow pixels of the man layer became invisible. In turn, the yellow pixels of the lights layer affected the remaining visible channels of the man.
Specifying Layers
Normally you set blending options for a selected layer to affect all layers beneath it. One of the unique aspects of Knockout is the Deep option. For example, if you set the blending mode of any layer to Overlay with Knockout set to Deep, you will only apply Overlay to the Background layer. (It must be a Background layer for it to work. To convert a layer to a Background, choose Layer > New > Layer From Background.) In the example, the Yellow channel for the man layer is still deselected from the previous tip, but now the layer’s Blend Mode is set to Pin Light. With Knockout set to None, you would see the Pin Light mode applied to the lights layer below it. But after setting the Knockout to Deep, the Pin Light mode ignored the lights layer and was only applied to the Background layer.
Blending Conditionally

If you apply Overlay to a layer, it’s applied equally to all pixels. However, you can blend a range of colors based on brightness values, either on the selected layer or the underlying layer. With the Blend If option set to Gray, use the sliders to set the black and/or white points for the brightness range to be blended. The upshot is that pixels in the range above or below these values will be transparent and only pixels within the range are blended, which can create a grunge look. If you want to get detailed, specify colors to really fine-tune the blending. change the Blend If option to one of the color channels&mdash:it’s best to start with the predominant color—then move sliders to blend only for that color.
Smoothing the Blend

An image can look pixelated when the transition between two colors in a blend is too abrupt. If you get pixelation after blending conditionally, soften edges by creating a spread over which black and white points are applied. To split the range, Option/Alt-click a slider and drag one half to the left or right. This creates a more gradual blend—the wider the spread, the softer the transition.
Changing Your Mind
In the Blending Options dialog box (as with most dialog boxes in Photoshop), you can press Option/Alt at any time to transform the Cancel button to Reset, which will return settings to the state when the dialog box was last opened.

Saving the Blend

Once you’ve set all your layer’s blending options, save your blend as a style preset to apply to other layers or images. Click the New Style button in the Layer Style dialog box. Give the new style a name, make sure that Include Layer Blending Options is checked, and click OK. The new style will be in the Styles palette.

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Jason Cranford Teague has written numerous computer design books, including Photoshop CS at Your Fingertips and Final Cut Pro and the Art of Filmmaking.