Tài liệu Photoshop cs5 by Dayley part 45 doc

Chapter 10: All about Layers 305 FIGURE 10.9 The Layers panel has different types of lock settings that allow you to protect your layers. Lock Transparent Pixels Lock Image Pixels Lock Position Lock All Blending modes Blending modes create amazing special effects by changing the way layers affect each other. At the beginning of this chapter, I asked you to imagine that layers were like transparencies stacked on top of one another. Using Blending modes is an example of how using digital technology has taken this idea one step further. Imagine that your transparencies are made of gel rather than plastic, and that rather than sitting on top of one another, they can blend with each other. Then imagine that you can determine which areas of the images on your transparencies would blend and how. Last but not least, imagine that you finish blending them, and you hate the result, but you find that you can pull them apart and start all over with your original images. But blending modes do more than blend two images together. They can be used on any layer that is added to your Layers panel. You can use them to change the way a layer style is applied, to blend a pattern into an image, or even to change an adjustment layer into a special effect. The drop-down menu at the top of the Layers panel shown in Figure 10.10 shows the different blending modes you can use to choose how the selected layer affects the layers under it. The blending modes are divided into six general categories, explained in the following sections. 16_584743-ch10.indd 30516_584743-ch10.indd 305 5/3/10 10:25 AM5/3/10 10:25 AM Part III: Selections, Layers, and Channels 306 FIGURE 10.10 The Blending modes menu Normal and dissolve blending modes The Normal blending mode is the default setting in the Layers panel, and when it is used, layers act as you would expect. When the opacity of a layer is set to 100 percent, any pixels in that layer completely cover the layers below. As you reduce the opacity of a Normal layer, it becomes univer- sally more transparent. If you choose the Dissolve blending mode, it looks the same at 100 percent opacity as the Normal mode, but as you reduce the opacity, the selected layer disintegrates or dis- solves, losing pixels rather than opacity. l Normal: This is the default option. The blend is applied uniformly by painting each pixel based on the layer value and opacity setting to make it the resulting pixel. 16_584743-ch10.indd 30616_584743-ch10.indd 306 5/3/10 10:25 AM5/3/10 10:25 AM Chapter 10: All about Layers 307 l Dissolve: This blend is applied by randomly replacing the pixels with either the base value or the layer value, depending on the pixel location and the opacity setting. Using this option allows you to dissipate the effect of the layer more than just changing the opacity. Darkening blending modes The next group within the Blending modes menu contains darkening effects. Each of these five blending filters leaves the darker areas of the selected layer opaque and creates translucency in the lighter areas of the image. l Darken: The blend is applied by replacing the pixels with the darker of the base value or the layer value. In other words, the layer is applied only to pixels in the underlying image that are lighter than the value of the layer pixel. This has the effect of darkening the image and can be extremely useful if applying filters to overexposed images. l Multiply: The blend is applied by multiplying the base value of each pixel by the layer pixel value. Multiplying a pixel by black always produces black, and multiplying a pixel by white leaves the pixel value unchanged. This mode has the overall affect of darkening the image. l Color Burn: The blend is applied by darkening the base channel based on the blended color by increasing the contrast between the two. This has the effect of darkening the image as well as increasing color contrasts. l Linear Burn: This darkens the image as it applies the blend by decreasing the brightness based on the value of layer pixel. l Darken Color: The blend is applied by replacing each channel of a pixel with the darker between the base pixel channel and the layer pixel channel. This option works a bit better than using the Darken mode because it uses the darkest values from each channel to cre- ate the resulting color. Lightening blending modes The lightening blending modes work opposite of the darkening blending modes: Instead of leaving the dark areas opaque, the lighter areas of the selected layer remain opaque and the dark areas are translucent. l Lighten: The blend is applied by replacing the pixels with the lighter of the base value or the layer value. This has the effect of lightening the image and can be extremely useful if applying filters to underexposed images. l Screen: The blend is applied by multiplying the inverse of the channel values of the layer and base pixels. This results in a lighter color than either the layer value or the base value. This has the same effect as projecting multiple photographic slides on top of each other. l Color Dodge: This applies the blend by decreasing the contrast between the color of the channels in the layer pixel and the base pixels. This lightens the base pixels using the layer pixel values. l Linear Dodge (Add): This lightens the images as it applies the blend by increasing the brightness based on the layer value of each channel. 16_584743-ch10.indd 30716_584743-ch10.indd 307 5/3/10 10:25 AM5/3/10 10:25 AM Part III: Selections, Layers, and Channels 308 l Lighter Color: The blend is applied by replacing each channel of a pixel with the lighter between the base pixel channel and the layer pixel channel. This option works a bit better than using the Lighten mode because it uses the darkest values from each channel to cre- ate the resulting color. Adding contrast blending modes These blending modes create contrast between the selected layers and the layers under it, making the lighter areas lighter and the darker areas darker. Here’s information you need to know to apply these modes: l Overlay: This applies the blend by mixing the layer values with the base pixels while pre- serving the shadows and highlights. This reduces the effect of extreme layer adjustments that dramatically reduce the detail in the original image. l Soft Light: This applies the blend based on the gray value of the filtered pixel. If the value of the layer pixel is darker than 50 percent gray, then the base pixel is darkened using a multiplying method. If the value of the layer pixel is lighter than 50 percent gray, then the base pixel is lightened using a dodging method. This has a similar effect to shining a dif- fused spotlight on the image. l Hard Light: This applies the blend based on the gray value of the layer pixel. If the value of the layer pixel is darker than 50 percent gray, then the base pixel is darkened using a multiplying method. If the value of the layer pixel is lighter than 50 percent gray, then the base pixel is lightened using a screening method. This has a similar effect to shining a harsh spotlight on the image. This option is great for adding shadows while applying the filter. l Vivid Light: This applies the blend based on the gray value of the layer pixel. If the value of the layer pixel is darker than 50 percent gray, then the base pixel is darkened by increasing the contrast. If the value of the filtered pixel is lighter than 50 percent gray, then the base pixel is lightened by decreasing the contrast. l Linear Light: The Linear light acts as a combination of Linear Burn, Linear Dodge, and Vivid Light. The lighter colors brighten, but not as much as using Linear Dodge; and the darker colors darken, but not as much as using Linear Burn. l Pin Light: This applies the filter based on the gray value of the layer pixel. If the value of the layer pixel is darker than 50 percent gray, then the darker of the layer pixel and base pixel is used. If the value of the layer pixel is lighter than 50 percent gray, then the lighter of the layer pixel and base pixel is used. l Hard Mix: This adds the value of each RGB channel in the layer pixel to the correspond- ing RGB channel in the base pixel. The values above 255 and below 0 are clipped, so this can result in a large loss of detail. Using difference blending modes These blending modes blend the layers based on the difference between the two layers: 16_584743-ch10.indd 30816_584743-ch10.indd 308 5/3/10 10:25 AM5/3/10 10:25 AM Chapter 10: All about Layers 309 l Difference: This applies the blend by setting the resulting pixel to the value of the differ- ence between the upper pixel and the base pixel. Blending white inverts the pixel value, and blending black results in no change. l Exclusion: This works similarly to the Difference blend mode, but has less contrast. l Subtract: Subtracts the brightness value of the pixels in the source layer from the corre- sponding pixels in the target layer. The result is divided by a scale factor and then added to the offset value. The brighter the source, the more the blending mode subtracts. l Divide: Divides the brightness value of the pixels in the source layer from the correspond- ing pixels in the target layer. This option has a much larger variance then the Subtract blending mode. Color blending modes The final group of blending modes gives the selected layer a color influence over the layers under it: l Hue: This applies the blend by creating the resulting pixel using the luminance and satu- ration of the base pixel but the hue of the filtered pixel. This reduces the blend to affect only the hue of the base layer. l Saturation: This applies the blend by creating the resulting pixel using the luminance and hue of the base pixel but the saturation of the filtered pixel. This reduces the blend to affect only the saturation of the original layer. l Color: This applies the blend by creating the resulting pixel using the luminance of the base pixel but the hue and saturation of the filtered pixel. This limits the blend so that it does not affect the brightness of the original layer. l Luminosity: This applies the blend by creating the resulting pixel using the hue and satu- ration of the base pixel but the luminance of the blended pixel. This allows you to apply so that it affects only the brightness of the original layer. Using blending modes As you can see, it’s actually hard to describe the effects that Blending modes can have on your image. The layers you are working with really make a difference in how the blending modes look, so the best way to get a feel for them is to jump in and play with them using your own images. I show two examples of how to do this. Here is an example of how to blend two images together using Blending modes: On the Web Site You can create this effect yourself or look at my finished PSD file by downloading Figure 10-11a, 10-11b, and 10-11c from the Web site. n 1. Open an image in Photoshop to be your base image. For the effect we are going to use in this example, a darker image would be best, such as the first photo shown in Figure 10.11. 16_584743-ch10.indd 30916_584743-ch10.indd 309 5/3/10 10:25 AM5/3/10 10:25 AM Part III: Selections, Layers, and Channels 310 2. Add a second image as a layer on top of the first image. This image should have highly contrasting light and dark areas, such as the second photo in Figure 10.11. 3. From the Blending modes drop-down menu, choose the Linear Dodge (Add) Blending mode. Make sure your top layer is selected. The Linear Dodge (Add) Blending mode is a lighten Blending mode, which means that only the lighter areas of the image are visible. The photo of the fireworks is ideal because only the fireworks themselves are now visible, as shown in the last image in Figure 10.11. FIGURE 10.11 Using the Linear Dodge (Add) Blending mode makes the lighter pixels in the fireworks image visible and the darker pixels transparent, leaving a great view of the image under- neath. Here is another example of using Blending modes. In this example, I am going to add a color cast to a photo. This is a good way to create sepia-toned images, but you can use any color you want: On the Web Site You can see the final image in color or try adding a color cast yourself by downloading Figure 10-12a and 10-12b from the Web site. n 1. Open an image to which you want to add a color cast. 2. Choose Solid Color from the New Adjustment Layer menu in the Layers panel. 16_584743-ch10.indd 31016_584743-ch10.indd 310 5/3/10 10:25 AM5/3/10 10:25 AM Chapter 10: All about Layers 311 The Color Picker dialog box opens. 3. Choose a color to tint your photo. A dark brown creates a beautiful sepia-tone, but you can choose any color you want. (The dark browns can be found in the orange/reds at the bottom of the color spectrum.) 4. Click OK. The color fill is added as a new layer, as shown in Figure 10.12, leaving your image look- ing like a rectangle of solid color. 5. Choose Color from the Blending modes drop-down menu in the Layers panel. Be sure the color layer is selected when you do this. Now the color fill affects the image by using the brightness values of the image to map the color fill onto the image, as you can see in Figure 10.12. FIGURE 10.12 Although you can’t actually see the color cast, you can see by the Layers panel that the Blending mode has been applied. The previous exercise created a solid color cast. The best thing about using Blending modes is that the effects are only as limited as your creativity. You can change the look of this effect by reducing the opacity of the color fill layer, or better yet, changing your image into a black and white photo before doing so. 16_584743-ch10.indd 31116_584743-ch10.indd 311 5/3/10 10:25 AM5/3/10 10:25 AM Part III: Selections, Layers, and Channels 312 Tip When creating your own color casts, create a Levels adjustment layer over your image after the color cast has been created. Adjusting the levels can increase the contrast of your image and give the color cast more “pop.” n Linking layers On the bottom of the Layers panel is a whole new set of icons for working with layers. The left icon, as shown in Figure 10.13, is the Link layers icon. Layers that are linked move together and are resized together, and creating a selection on one also creates a selection on all. To link layers, select two or more layers by holding down the Shift key to select contiguous layers, or holding down the Ctrl/Ô key to select layers that are not contiguous in the Layers panel. When you have two or more layers selected, the Link layers icon is active. Click it to link the selected lay- ers. The linked layers display a link icon, as shown in Figure 10.13. FIGURE 10.13 The most powerful tools in the Layers panel have deceivingly simple icons. Layer group Linked layers Create a new fill or adjustment layer Link layers Add layer style Add layer mask Create new group Create new layer Delete layer 16_584743-ch10.indd 31216_584743-ch10.indd 312 5/3/10 10:25 AM5/3/10 10:25 AM . The blend is applied by multiplying the base value of each pixel by the layer pixel value. Multiplying a pixel by black always produces black, and multiplying a pixel by white leaves the pixel. affect of darkening the image. l Color Burn: The blend is applied by darkening the base channel based on the blended color by increasing the contrast between the two. This has the effect of. This darkens the image as it applies the blend by decreasing the brightness based on the value of layer pixel. l Darken Color: The blend is applied by replacing each channel of a pixel with the