Blending Modes and Transparency


Simply placing one layer on top of another layer covers up the bottom layer. Sometimes this is just what you want, but Photoshop’s layers allow you much more control than that. You can control the opacity (or transparency) of any layer. You can also change a layer’s blending mode, which changes the way that layer interacts with any layers beneath it.

Work with Opacity and Fill

Each layer has two settings which control its transparency or lack thereof: Opacity and Fill.

The difference between Opacity and Fill is not initially very clear. A layer containing a photograph looks the same at 50 percent Opacity as it does at 50 percent Fill, as you can see in Figures 4-17a and 4-17b. The difference is that Fill affects the pixels in the layer; it does not affect any layer effects such as drop shadows. Opacity, on the other hand, affects the pixels in the layer and any layer effects. Look at Figures 4-18a and 4-18b. These show a text layer with a Stroke effect applied. As you can see, reducing the Fill to 50 percent makes the actual text partially transparent while leaving the Stroke effect entirely intact. On the other hand, reducing the Opacity to 50 percent renders the entire layer, including the Stroke effect, partially transparent.


Figure 4-17a: Here is a photo layer at 50 percent Opacity.


Figure 4-17b: Here is a photo layer at 50 percent Fill.

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Figure 4-18a: Here you see text with a blue Stroke effect applied.

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Figure 4-18b: Reducing the Fill leaves layer effects intact.

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Figure 4-18c: Reducing the Opacity affects the entire layer.

Adjust Layer Opacity

  1. With an image open in Photoshop, create a second layer using any of the methods given above.

  2. In the Layers palette, click the thumbnail of the top layer to select it.

  3. Locate the Opacity control at the top of the Layers palette.

  4. Click the arrow to the right of the current value, and use the drop-down slider to reduce the layer’s Opacity. The lower layer shows through, as shown in Figure 4-19.

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    Figure 4-19: Set a layer’s transparency in the Layers palette.

Use Blend Modes

So far, we have only explored layers using the Normal blending mode. But Photoshop has no less than 22 additional blend modes. Blend modes control the way Photoshop blends layers together. You can see many of them in Figure 4-20.

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Figure 4-20: Use Photoshop’s blend modes to combine layers for a multitude of different effects.

Change a Layer’s Blend Mode

You can change a layer’s blend mode at any time.

  1. In the Layers palette, locate the Blending mode drop-down list at the top. It probably shows the word Normal.

  2. Click the Blending mode. A menu of blending modes drops down.

  3. Click a new blending mode, such as Vivid Light, to observe the effect.

    Note

    By reducing a layer’s Fill to 0 percent, you can create layer effects such as drop shadows, without showing the shapes that create them.

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Use Common Blending Modes

Although you can choose from more than 20 layer blend modes, a few of them are especially handy.

Note

You can change the Opacity and Fill of layers in any blend mode, not just Normal.

Use Multiply Mode

A layer in Multiply mode always darkens the image (except where the layer is pure white or transparent in which case Multiply has no effect). Placing a copy of the mask in Figure 4-21 on a new layer in Multiply mode darkens the original everywhere except in areas of pure white. The lighter a pixel in the Multiply layer, the less it darkens the overall image.


Figure 4-21: This is the original Mask photograph.

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Use Screen Mode

Screen mode is the opposite of Multiply mode. A layer in Screen mode always lightens the image (except where the layer is pure black or transparent in which case it has no effect). Placing a copy of the mask in Figure 4-21 on a new layer in Screen mode lightens the original everywhere except in areas of pure black. The lighter a pixel in the Multiply layer, the more it lightens the overall image.

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Tip

If you like the effect a blend mode produces but want to tone it down a bit, reduce the Opacity of the layer.

Note

You cannot change the original background layer’s blending mode.

Tip

It’s almost impossible to picture in advance what a given blend mode will look like. When combining layers, try out the different blend modes to see how they look.

Create an Adjustment Layer

Layers don’t always contain images or fills; they can also be adjustment layers. Adjustment layers allow you to make adjustments to an image without making any permanent changes to it. Your original image is preserved and you can tweak the adjustment further at any time.

To create an adjustment layer:

  1. Open a photograph in Photoshop.

  2. Click Layer | New Adjustment Layer. You are presented with a submenu of adjustments you can make to your image, as shown in Figure 4-22.

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    Figure 4-22: You can create a new adjustment layer via the Layer menu.

  3. For now, choose Levels (although you could choose any of the adjustments from the menu.) The New Layer dialog box appears. Click OK.

  4. The Levels dialog box appears. Drag on the center of the three sliders beneath the image thumbnail. Drag far enough to one side to make the image significantly darker or lighter.

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  5. Click OK.

The image looks very different, but the original photo layer is actually untouched. To see this:

In the Layers palette, click the Eye at the left of the adjustment layer to temporarily hide it. The photo returns to normal, as shown in Figure 4-23.


Figure 4-23: Hiding the adjustment layer shows that the original scan is untouched.

Make Changes to an Adjustment Layer

In the Layers palette, double-click the layer thumbnail to reopen the appropriate dialog box (e.g., Levels).

Delete an Adjustment Layer

In the Layers palette, click the Adjustment layer you want to delete, and drag it to the Trashcan icon at the bottom of the palette.

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QuickSteps—Creating a Quick Sepia Tone

Blending modes make it easy to tint an image in Photoshop.

  1. Open any color or black-and-white photograph in Photoshop, such as the one in Figure 4-24.

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    Figure 4-24: Here is a scanned photograph.

  2. Click the Create A New Layer button at the bottom of the Layers palette, or click Layer | New | Layer to create a new blank layer.

  3. Click the foreground color in the Toolbox, and use the Color Picker to choose a dark orange or brown. RGB 166, 131, 45 works well.

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  4. Click OK to accept the new foreground color.

  5. Press alt+delete to fill the new layer with your chosen color. This results in a solid brown picture.

  6. To apply the brown color to the underlying image, click the solid brown layer in the Layers palette to select it.

  7. Click the Blending Modes box, and choose Color from the pop-up menu.

    The results are seen in Figure 4-25. The color of every pixel in the underlying photo is replaced by the sepia color from the top layer. Luminance (the darkness or lightness of the pixels) is unaffected. This technique could be used to add any amount of any tint to an image. It works on black-and-white photos as well, as seen in Figure 4-26.

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    Figure 4-25: The original photo is sepia toned, thanks to Color blend mode.

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    Figure 4-26: The original black-and-white scan is on the left; the sepia-toned version is on the right.

    To fine-tune the effect:

    • Fill the color layer with a different color.

      –Or–

    • Adjust the Opacity of the color layer.

      Note

      If you select Use Previous Layer To Create Clipping Mask when creating an adjustment layer, the new adjustment layer will only affect the layer directly beneath it.

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Create a Collage

The combination of layer blend modes, masking, and layer effects makes Photoshop a powerful tool for creating collages and multi-element compositions of all sorts. Here is an exercise that goes through the whole process, demonstrating the potential steps you might take.

Choose Your Images

Perhaps you have been given the task of designing the cover of a fictional novel called “Dust in my Teeth.”

  1. First, browse your collection of stock photographs, and find a few that seem to fit the title, including a photo of some false teeth and a photo of some worn leather.

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  2. Create a new Photoshop document the size of the book cover, say, 5 inches by 8, and drag both images into it on new layers. Now comes the fun part: combining the layers in different ways to see what comes up.

Blend the Layers

  1. Placing the teeth over the leather at 50 percent opacity, as shown in Figure 4-27, shows that the teeth line up nicely with the seams in the leather, but the effect isn’t very pleasing.

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    Figure 4-27: With the teeth layer at 50 percent Opacity, the leather shows through.

  2. Placing the teeth over the leather in Multiply mode produces an intriguing blend, as shown in Figure 4-28. The dark cracks in the leather make the teeth look dirty, but the result is too dark. Remember that Multiply mode darkens underlying layers; the dark leather completely overpowers the lighter teeth.

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    Figure 4-28: The teeth layer in Multiply mode makes things too dark.

  3. Placing the teeth over the leather in Screen mode, as shown in Figure 4-29, doesn’t work. Screen mode always lightens, and the lighter tooth layer completely washes out the darker underlying leather layer.

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    Figure 4-29: Placing the teeth in Screen mode washes everything out.

  4. Trying different blend modes eventually leads you to Overlay mode, as show in Figure 4-30. This is pretty good. It has the same “dirty teeth” effect as Multiply mode produced, but the image is much brighter and easier to “read.” (Overlay tends to preserve the highlights and shadows of the base layer while mixing in the colors of the top—Overlay—layer.) To heighten the effect, you could duplicate the tooth layer, leaving the new layer in Overlay mode, as well. The results are shown in Figure 4-31.

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    Figure 4-30: Overlay mode is the best so far.

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    Figure 4-31: Placing two copies of the teeth layer in Overlay mode heightens the effect.

  5. You might decide the image is a little too bright. To darken things up a bit, you could duplicate the leather layer, placing the new duplicate above the teeth layers in Multiply mode. (Nothing darkens like Multiply.) You can control the strength of the effect by reducing the Opacity of the Multiply layer, as shown in Figure 4-32.

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    Figure 4-32: A copy of the leather layer, on top in Multiply mode, darkens the image up again.

    Tip

    Name your layers as you go, so you can see at a glance what’s what.

Add Some Text

You might want to add some text.

Find a suitable font and begin to create the look of letters carved into the leather; for example, you could add a Bevel layer effect, using the Pillow Emboss style, as shown in Figure 4-33.

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Figure 4-33: Layer effects make the text look hand carved into the leather.

The final results might look like this:

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Pretty nifty, and created with two stock photos and a few words … plus, of course, plenty of blending modes, transparency, and layer effects.




Photoshop CS QuickSteps
Photoshop CS4 QuickSteps
ISBN: 0071625372
EAN: 2147483647
Year: 2006
Pages: 59

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