Working with the Advanced Blending Options in Photoshop

If you want to get serious about layers, then you need to know about the Advanced Blending Options, found in the Layer Style dialog box. These options allow you to tailor the way your layer styles and blend modes interact with your layers. Getting to the advanced options is just like accessing opacity and blend modes: You can double-click a layer thumbnail, choose Layer-->Layer Style-->Blending Options, or choose Blending Options from the Layers palette pop-up menu. The massive Layer Style dialog box rears its multipaneled head.

Advanced options to blend with
The advanced options are not for the faint of heart. To be frank, the options are, well, advanced, so you might find them a tad too eggheady for your taste, but if not, here you go:
- Fill Opacity
- Channels: This option allows you to restrict your blending options to specific channels only.
- Knockout: This option allows you to specify which layers have holes in them so that you can view the layers underneath. You first have to use the Fill Opacity option to set the
opacity of the knockout. The lower the opacity, the more the hole shows; therefore, set it to 0% to see all the way through. Set the Knockout to Shallow to create a hole through one layer set or a clipping group. Set the Knockout to Deep to create a hole all the way through to the background. If you’re just working with layers, and not sets or clipping groups, the knockout cuts through to the background. If there is no background, it cuts through to transparency.
- Blend Interior Effects as Group: This option applies the blend mode of the layer to interior layer effects, such as inner glows, satin and color overlay, and so on. Deselect this option, and the blend mode does not affect the layer effects.
- Blend Clipped Layers as Group: The blend mode of the bottom layer in the clipping group affects all the other layers in the group. Deselect this option, and each layer retains its own blend mode and appearance.
- Transparency Shapes Layer: Confines layer effects and knockouts to opaque areas of a layer. Deselect this option, and the mode applies layer effects and knockouts to the entire layer.
- Layer Mask Hides Effects: Confines layer effects to the area designated by the layer mask.
- Vector Mask Hides Effects: Confines layer effects to the area designated by a vector mask.

Blend If options
By using the slider bars, you can specify which colors are visible in the active layer and which colors show through from the underlying layers. You can choose a specific channel from the Blend If pop-up menu to apply the option to a single channel. The default channel of Gray affects all channels in the image.
- The This Layer slider bar allows you to set a blending range. In other words, you can hide certain colors according to the brightness values in the active layer. By dragging the black triangle to the right, you exclude darker colors. By dragging the white triangle to the left, you exclude lighter colors.
- The Underlying Layers slider bar forces the colors from the underlying layers to show through the active layer. Again, dragging the black and white triangles excludes ranges of colors.
Excluding and forcing colors can result in some harsh color transitions. You can provide for a smoother transition between blended and unblended areas by splitting the slider into two parts. This allows the pixels to gradually fade to transparency. Alt+drag (Option+drag on the Mac) on either the black or white triangle in either slider bar to split the triangle into two halves. The left and right triangles mark the beginning and end of the blending range, where pixels will fade into or out of view.