Photoshop 6 for Windows Bible- P22

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Photoshop 6 for Windows Bible- P22:If you are reading this foreword, it probably means that you’ve purchased a copy of Adobe Photoshop 6.0, and for that I and the rest of the Photoshop team at Adobe thank you. If you own a previous edition of the Photoshop Bible, you probably know what to expect. If not, then get ready for an interesting trip.

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Chapter 12 ✦ Working with Layers 601 And finally, here’s a question for all you folks who think you may have Photoshop mastered. Which of the brush modes (explained in Chapter 5) is the exact opposite of Lock Transparency? The answer is Behind. To see what I mean, turn off Lock Transparency. Then select the paintbrush tool and choose the Behind brush mode in the Options bar. Now paint. Photoshop applies the foreground color exclusively outside the transparency mask, thus protecting the opaque pixels. So it follows, when Lock Transparency is turned on, the Behind brush mode is dimmed. The moral? Behind is not a true brush mode and should not be grouped with the likes of Multiply and Screen in the Options bar. If you ask me, the better solution would be a Lock Opacity check box in the Layers palette. Alas, Adobe’s engineers seem to have better things to do, such as add three other Lock check boxes, none of which have the slightest thing to do with locking opacity. But just because I’ve been complaining about the Behind “brush mode” for the last, oh gosh, seven years doesn’t mean that I’m bitter or anything. Heavens no. I like to be ignored! It robs my life of meaning, which is precisely what I’m looking for. In fact, I think I’ll go and end it all right now. And for what? A check box. That’s all I want. A small and unobtrusive check box, possibly with a picture of my face next to it and a little caption reading, “Yes, Deke, you were right. Can you ever forgive us for being such knot-heads?” I mean, really, am I asking too much? So, in conclusion, Lock Transparency is your friend; Behind is the tool of Satan. Too bad so few things in the world are this black and white. Creating layer-specific masks In addition to the transparency mask that accompanies every layer (except the background), you can add a mask to a layer to make certain pixels in the layer transparent. Now, you might ask, “Won’t simply erasing portions of a layer make those portions transparent?” The answer, of course, is yes. And I hasten to add, that was a keen insight on your part. But when you erase, you delete pixels perma- nently. By creating a layer mask, you instead make pixels temporarily transparent. You can return several months later and bring those pixels back to life again simply by adjusting the mask. So layer masks add yet another level of flexibility to a pro- gram that’s already a veritable image-editing contortionist. To create a layer mask, select the layer you want to mask and choose Layer ➪ Add Layer Mask ➪ Reveal All. Or more simply, click the layer mask icon at the bottom of the Layers palette, as labeled in Figure 12-34. A second thumbnail preview appears to the left of the layer name, also labeled in the figure. A second outline around the preview shows the layer mask is active. Tip If the second outline is hard to see, keep your eye on the icon directly to the left of the layer name. If the icon is a paintbrush, the layer and not the mask is active. If the icon is a little dotted circle, the mask is active.
602 Part IV ✦ Layers, Objects, and Text Indicates layer mask is active Link icon Layer mask thumbnail Layer mask icon Figure 12-34: The black area in the layer mask (which you can see in the thumbnail view, top right) translates to transparent pixels in the layer. To edit the mask, simply paint in the image window. Paint with black to make pixels transparent. Because black represents deselected pixels in an image, it makes these pixels transparent in a layer. Paint with white to make pixels opaque. Thankfully, Photoshop is smart enough to make the default foreground color in a layer mask white and the default background color black. This ensures that paint- ing with the paintbrush or airbrush makes pixels opaque, whereas painting with the eraser makes them transparent, just as you would expect. In Figure 12-34, I created a feathered oval, inversed it, and filled it with black by pressing Ctrl+Backspace. This results in a soft vignette around the layer. If I decide
Chapter 12 ✦ Working with Layers 603 I eliminated too much of the hair, not to worry. I merely paint with white to bring it back again. Photoshop goes nuts in the layer mask department, adding lots of bells and whis- tles to make the function both convenient and powerful. Here’s everything you need to know: ✦ Reveal Selection: If you select some portion of your layer, Photoshop auto- matically converts the selection to a layer mask when you click the layer mask icon at the bottom of the palette. The area outside the selection becomes transparent. (The corresponding command is Layer ➪ Add Layer Mask ➪ Reveal Selection.) Tip ✦ Hide Selection: You can also choose to reverse the prospective mask, making the area inside the selection transparent and the area outside opaque. To do this, choose Layer ➪ Add Layer Mask ➪ Hide Selection. Or better yet, Alt-click the layer mask icon in the Layers palette. ✦ Hide everything: To begin with a black mask that hides everything, choose Layer ➪ Add Layer Mask ➪ Hide All. Or press Ctrl+D to deselect everything and then Alt-click the layer mask icon. Tip ✦ View the mask: Photoshop regards a layer mask as a layer-specific channel. You can actually see it listed in italics in the Channels palette. To view the mask on its own — as a black-and-white image — Alt-click the layer mask thumbnail in the Layers palette. Alt-click again to view the image instead. ✦ Layer mask rubylith: To view the mask as a red overlay, Shift+Alt-click the layer mask icon. Or simply press the backslash key, \, which is above the Enter key. Tip After you have both layer and mask visible at once, you can hide the mask by pressing \, or you can hide the layer and view only the mask by pressing the tilde key (~). So many alternatives! ✦ Change the overlay color: Double-click the layer mask thumbnail to access the Layer Mask Display Options dialog box, which enables you to change the color and opacity of the rubylith. ✦ Turn off the mask: You can temporarily disable the mask by Shift-clicking on the mask thumbnail. A red X covers the thumbnail when it’s disabled, and all masked pixels in the layer appear opaque. Shift-click again to put the mask back in working order. ✦ Switch between layer and mask: As you become more familiar with layer masks, you’ll switch back and forth between layer and mask quite frequently, editing the layer one minute and editing the mask the next. You can switch between layer and mask by clicking on their respective thumbnails. As I men- tioned, look to the icon to the left of the layer name to see whether the layer or the mask is active.
604 Part IV ✦ Layers, Objects, and Text Tip You can also switch between layer and mask from the keyboard. Press Ctrl+tilde (~) to make the layer active. Press Ctrl+\ to switch to the mask. ✦ Link layer and mask: A little link icon appears between the layer and mask thumbnails in the Layers palette. When the link icon is visible, you can move or transform the mask and layer as one. If you click the link icon to turn it off, the layer and mask move independently. (You can always move a selected region of the mask or layer independently of the other.) ✦ Convert mask to selection: As with all masks, you can convert a layer mask to a selection. To do so, Ctrl-click the layer mask icon. Throw in the Shift and Alt keys if you want to add or subtract the layer mask with an existing selection outline. Photoshop ✦ In Photoshop 6, you can apply a mask to a set of layers. Just select the set and 6 click the layer mask icon. The mask affects all layers in the set. If a layer in the set contains its own mask, no worries; Photoshop’s smart enough to figure out how to mix them together. For another method of masking multiple layers, see the section “Masking groups of layers,” coming up soon. When and if you finish using the mask — you can leave it in force as long as you like — you can choose Layer ➪ Remove Layer Mask. Or just drag the layer mask thumbnail to the trash can icon. Either way, an alert box asks whether you want to discard the mask or permanently apply it to the layer. Click the button that corresponds to your innermost desires. Pasting inside a selection outline One command, Edit ➪ Paste Into (Ctrl+Shift+V), creates a layer mask automatically. Choose the Paste Into command to paste the contents of the Clipboard into the cur- rent selection, so that the selection acts as a mask. Because Photoshop pastes to a new layer, it converts the selection into a layer mask. But here’s the interesting part: By default, Photoshop turns off the link between the layer and the mask. This way, you can Ctrl-drag the layer inside a fixed mask to position the pasted image. Tip Once upon a time in Photoshop, a command existed named Edit ➪ Paste Behind. (Or something like that. It might have been Paste in Back. My memory’s a little hazy.) The command (whatever its name) pasted a copied image in back of a selec- tion. Although the command is gone, its spirit still lives. Now you press Alt when choosing Edit ➪ Paste Into. Or just press Ctrl+Shift+Alt+V. Photoshop creates a new layer with an inverted layer mask, masking away the selected area. Masking groups of layers About now, you may be growing fatigued with the topic of layering masking. But one more option requires your immediate attention. You can group multiple layers into
Chapter 12 ✦ Working with Layers 605 something called a clipping group, in which the lowest layer in the group masks the others. Where the lowest layer is transparent, the other layers are hidden; where the lowest layer is opaque, the contents of the other layers are visible. Note Despite the similarities in name, a clipping group bears no relation to a clipping path. That is, a clipping group doesn’t allow you to prepare transparent areas for import into QuarkXPress and the like. There are two ways to create a clipping group: ✦ Alt-click the horizontal line between any two layers to group them into a sin- gle unit. Your cursor changes to the group cursor labeled in Figure 12-35 when you press Alt; the horizontal line becomes dotted after you click. To break the layers apart again, Alt-click the dotted line to make it solid. Group cursor Figure 12-35: Alt-click the horizontal line between two layers to group them.
606 Part IV ✦ Layers, Objects, and Text ✦ Select the higher of the two layers you want to combine into a clipping group. Then choose Layer ➪ Group with Previous or press Ctrl+G. To make the layers independent again, choose Layer ➪ Ungroup (Ctrl+Shift+G). Figures 12-35 and 12-36 demonstrate two steps in a piece of artwork I created for Macworld magazine. I had already created some text on an independent layer using the type tool (the subject of the next chapter), and I wanted to fill the text with water. So I added some photographs I shot of a swimming pool to a layer above the text, as shown in Figure 12-35. Then I combined text and pool images into a clipping group. Because the text was beneath the water, Photoshop masked the pool images accord- ing to the transparency mask assigned to the text. The result is a water pattern that exactly fills the type, as in Figure 12-36. (For a full-color version of these figures, see Color Plate 12-1.) Clipping group Figure 12-36: After combining pool water and type layers into a single clipping group, Photoshop applies the type layer’s transparency mask to the pool layer.
Chapter 12 ✦ Working with Layers 607 Note If you’re familiar with Illustrator, you may recognize this clipping group metaphor as a relative to Illustrator’s clipping mask. One object in the illustration acts as a mask for a collection of additional objects. In Illustrator, however, the topmost object in the group is the mask, not the bottom one. So much for consistency. ✦ ✦ ✦
The Wonders of Blend Modes 13 C H A P T E R ✦ ✦ ✦ ✦ In This Chapter Modifying the Opacity Mixing Images Together value There must be 50 ways to combine and compare differently Using blend modes to mix the active layer with colored pixels in Photoshop. So far, we’ve seen how you can the ones behind it smear and blur pixels into each other, select pixels using other pixels, layer pixels in front of pixels, compare a pixel to Selecting blend modes its neighbors using automated filters, and more. Any time that from the keyboard you edit, mask, composite, filter, or color correct an image, you’re actually breeding the image with itself or with other Applying opposite blend modes: Overlay images to create a new and unique offspring. and Hard Light, Color and Luminosity This chapter explores the final and ultimate experiment in Photoshop’s great genetics laboratory. Blend modes, also Sandwiching a heavily called calculations, permit you to mix the color of a pixel filtered image between with that of every pixel in a straight line beneath it. A single two unfiltered originals blend mode is as powerful as a mask, a filter, and a color map Taking advantage of combined, and best of all, it’s temporary. As long as one image the new Advanced remains layered in front of another, you can replace one calcu- Blending options lation with another as easily as you change a letter of text in a word processor. Fading pixels according to brightness values To appreciate the most rudimentary power of blend modes, using the Layer Style consider Figure 13-1. The first image shows a terrestrial thrill dialog box seeker composited in front of the Apollo crew’s old stomping Understanding the grounds. Both layers are as opaque as if you had cut them out advantages and with scissors and glued them together. (Granted, you’d have disadvantages of to be very skilled with scissors.) The antialiased edges of the channel operations parachute mix slightly with the moon pixels below them. But beyond that, every pixel is a digital hermit, steadfastly avoid- Mixing same-sized images with the Apply ing interaction. Image command Using the Add and Subtract blend modes Modifying selection outlines and masks using the Calculations command ✦ ✦ ✦ ✦
610 Part IV ✦ Layers, Objects, and Text Figure 13-1: Layers permit you to combine images from different sources (left), but blend modes permit you to mix images together to create intriguing if sometimes unexpected interactions (right). The second image in Figure 13-1 paints a different picture. Here I’ve created several clones of the parachute and moon and mixed them together using Photoshop’s con- siderable array of calculation capabilities. Although I used just two images, I com- posited them onto ten layers, only one of which — the background layer — was fully opaque. I don’t know if it’s moon men invading earth or the other way around, but whatever it is, it wouldn’t have been possible without blend modes and their ilk. Photoshop gives you three ways to mix images: ✦ The Layers palette: You can combine the active layer with underlying pixels using the Opacity value and blend mode pop-up menu, both members of the Layers palette. Figure 13-2 shows these two illustrious items in the context of the layers list for Figure 13-1. To learn everything there is to know about the Opacity value and blend mode pop-up menu, read the next section.
Chapter 13 ✦ The Wonders of Blend Modes 611 Blend mode pop-up menu Opacity slider Figure 13-2: The list of layers in the Invasion Moon composition, with the blend mode pop-up menu proudly displayed on the right. Photoshop ✦ Blending options: Double-click a layer name in the Layers palette to display 6 the new Layer Style dialog box, which contains controls formerly found in the Layer Options dialog box and more. Along with the standard Opacity slider and blend mode pop-up menu, you get an assortment of advanced blending options. Using the Blend If sliders, you can drop colors out of the active layer and force colors to show through from layers below. This is one of Photoshop’s oldest, finest, and least used features. Adding to this capability, Photoshop 6 provides a Knockout option, which enables you to blend a layer with one that’s not immediately below. In addition, you can blend individual color channels inde- pendently and choose to blend a filled area with or without any interior layer effects (such as an inner glow).
612 Part IV ✦ Layers, Objects, and Text ✦ Channel operations: The so-called channel operations permit you to com- bine two open images of identical size, or one image with itself. Photoshop offers two commands for this purpose, Image ➪ Apply Image and Image ➪ Calculations. Unusually complex and completely lacking in sizing and place- ment functions, these commands provide access to two unique blend modes named Add and Subtract. Simply put, unless a technique involves the Add or Subtract mode, or you want to clone two images into a third image win- dow, you can mix images with greater ease, flexibility, and feedback using the Layers palette. For more on this lively topic, see the “Using Channel Operation Commands” section later in this chapter. Photoshop 6 Photoshop 6 also enables you to blend layers on a channel-by-channel basis, an option you can explore in the section “Blending individual color channels.” Blend modes are not Photoshop’s most straightforward feature. There may even come a time when you utter the words, “Blend modes are stupid.” They demand a generous supply of experimentation, and even then they’ll fool you. I was a math major in college (with a double-major in art, for what it’s worth), so I well under- stand the elementary arithmetic behind Photoshop’s calculations. And yet, despite roughly a decade of experience with blend modes in Photoshop and other programs, I am frequently surprised by their outcome. The key, therefore, is to combine a basic understanding of how blend modes and other compositing features work with your natural willingness to experiment. Sometime when you don’t have a deadline looming over your head, take some multi- layered composition you have lying around and hit it with a few calculations. Even if the result is a disaster that you wouldn’t share with your mother, let alone a client, you can consider it time well spent. Using Opacity and Blend Modes This is not the first time in this book that I’ve touched on the Opacity value or the blend mode pop-up menu. And given that the Layers palette’s blend modes mimic the brush modes (both in name and in function) as I discussed in “The 19 paint tool modes” section near the end of Chapter 5, we’re covering some familiar territory. But you’ll soon find that there’s a significant difference between laying down a sin- gle color with a brush and merging the all the colors that inhabit a single layer. This difference is the stuff of the following pages. Note Incidentally, both the Opacity and blend mode options are dimmed when working on the background layer or in a single-layer image. There’s nothing underneath, so there’s nothing to mix. Naturally, this goes double when editing black-and-white and indexed images or when editing masks, because neither of these circumstances supports layers.
Chapter 13 ✦ The Wonders of Blend Modes 613 The Opacity setting The Opacity value is the easiest of the layer mixers to understand. It permits you to mix the active layer with the layers beneath it in prescribed portions. It’s sort of like mixing a drink. Suppose you pour one part vermouth and four parts gin into a martini glass. (Any martini enthusiast knows that’s too much vermouth, but bear with me on this one.) The resulting beverage is 1⁄ 5 vermouth and 4⁄ 5 gin. If the vermouth were a layer, you could achieve the same effect by setting the Opacity to 20 percent. This implies that 20 percent of what you see is vermouth and the remaining 80 per- cent is underlying gin. Tip When any selection or navigation tool is active, you can change the Opacity setting for a layer from the keyboard. Press a single number key to change the Opacity in 10-percent increments. That’s 1 for 10 percent, 2 for 20 percent, up to 0 for 100 per- cent — in order along the top of your keyboard. If you have the urge to be more pre- cise, press two keys in a row quickly to specify an exact two-digit Opacity value. You also can change the opacity by dragging the Opacity slider in the Layers palette (see Figure 13-2). Click the arrowhead to the right of the Opacity value to display the slider bar, and then drag the triangle to change the value. Or press the up and down arrows to nudge the triangle along. Press Shift with the arrow key to nudge in 10-per- cent increments. Press Enter to confirm the slider setting. Press Escape to cancel and restore the previous setting. Photoshop 6 For yet another opacity maneuver, double-click the layer name to open the Layer Style dialog box. At the top of this gargantuan dialog box, you find a standard Opacity slider. In the Advanced Blending section of the dialog box, you find the Fill Opacity slider, which adjusts the opacity of filled areas only — that is, any pixels not devoted to creating layer effects. You can vary the opacity of interior layer effects, such as an inner glow, along with the filled areas or leave those effects untouched as well. For more about these intriguing possibilities, visit the section “Applying Advanced Blending Options,” later in this chapter. The blend modes Photoshop offers a total of 17 blend modes. Thanks to the diminished role of floating selections, two former blend modes, Behind and Clear, are now officially ex-modes. Once upon a time, Behind and Clear were quite useful for slipping floaters behind layers and cutting movable holes. But they became significantly more cumbersome in Version 4. Let us take a moment of silence to mourn their passing.
614 Part IV ✦ Layers, Objects, and Text Note Although the Behind and Clear modes are no longer available for layers, they are still available for use with the line and paint bucket tools and the Edit ➪ Fill and Edit ➪ Stroke commands. You must be working on a layer with the Lock Trans- parency check box turned off to use these modes. Okay, enough of that. The remaining 17 modes — Normal through Luminosity — are still alive and well, so I suppose we should count our blessings. As you read through my upcoming discussions, you can check out examples of the blend modes both in the accompanying grayscale figures and in Color Plate 13-1. The grayscale figures show the results of compositing the two images shown in Figure 13-3. The thinker is on top; the sunset is on bottom. The color plate features a series of Saturns layered against the stormy gaseous planet of Jupiter. Although the planets aren’t to scale — I understand that both bodies are several times larger than this book, for example — they do a fair job of showing the effects of Photoshop’s modes. Figure 13-3: To demonstrate the effects of Photoshop’s blend modes, I composit the thinker (top) against a sunset background (bottom). In each case, the blend mode is applied to the thinker.
Chapter 13 ✦ The Wonders of Blend Modes 615 Tip You can access every one of the blend modes from the keyboard by pressing Shift+Alt plus a letter, as long as the selected tool doesn’t offer blend mode options. (If the tool does support blend modes, the shortcuts set the mode for the tool and not the layer.) In addition, the dodge, burn, and sponge tools now respond to some Shift+Alt short- cuts: With dodge and burn, Shift+Alt plus the S, M, or H key sets the tool range pop- up menu to Shadow, Midtones, or Highlights, respectively. And with the sponge tool, S sets the tool to saturate mode, and D changes the tool to desaturate mode. Got all that? Good. Back to layer blend mode shortcuts. Some letters in the short- cuts make perfect sense — Shift+Alt+N for Normal, for example. Others are a bit of a stretch — such as Shift+Alt+I for Dissolve. Whether predictable or not, I list the letter in parentheses with each blend mode description. Note One more note: Every so often, I allude to a little something called a composite pixel. By this I mean the pixel color that results from all the mixing that’s going on beneath the active layer. For example, your document may contain hoards of layers with all sorts of blend modes in effect, but as long as you work on, say, Layer 23, Photoshop treats the image formed by Layers 1 through 22 as if it were one flat- tened image filled with a bunch of static composite pixels. Cool? Keen. So without any further notes and clarifications, here they are, the 17 blend modes, in order of appearance: ✦ Normal (N): In combination with an Opacity setting of 100 percent, this option displays every pixel in the active layer normally, regardless of the colors of the underlying image. When you use an Opacity of less than 100 percent, the color of each pixel in the active layer is averaged with the composite pixel in the layers behind it according to the Opacity value. ✦ Dissolve ( I ): This option specifically affects feathered or softened edges. If the active layer is entirely opaque with hard edges, this option has no effect. But when the edges of the layer are feathered, the Dissolve option randomizes the pixels along the edges. The first two images in Figure 13-4 compare a feathered layer subjected to the Normal and Dissolve modes. Dissolve also randomizes pixels when the Opacity value is set below 100 percent, as demon- strated in the final example in the figure. ✦ Multiply (M): To understand the Multiply and Screen modes, you have to use a little imagination. So here goes: Imagine that the active layer and the under- lying image are both photos on transparent slides. The Multiply mode pro- duces the same effect as holding those slides up to the light, one slide in front of the other. Because the light has to travel through two slides, the outcome is invariably a darker image that contains elements from both images. An exam- ple of the Multiply blend mode appears in Figure 13-5.
616 Part IV ✦ Layers, Objects, and Text Normal feather Dissolve feather 70% Dissolve Figure 13-4: Here I applied Normal (left) and Dissolve (middle) to a layer with heavily feathered edges. The final example shows the effect of Dissolve when I reduce the Opacity value to 70 percent. (The superimposed characters indicate the keyboard shortcuts Shift+Alt+N for Normal, Shift+Alt+I for Dissolve, and 7 for 70 percent opacity.) Figure 13-5: The Multiply blend mode produces the same effect as holding two overlapping transparencies up to the light. It always results in a darker image.
Chapter 13 ✦ The Wonders of Blend Modes 617 ✦ Screen (S): Still have those transparent slides from the Multiply analogy? Well, place them both in separate projectors and point them at the same screen and you get the same effect as Screen. Rather than creating a darker image, as you do with Multiply, you create a lighter image, as demonstrated in Figure 13-6 and Color Plate 13-1. You can use the Screen blend mode to emulate film that has been exposed multi- ple times. Ever seen Thomas Eakin’s pioneering Jumping Figure, which shows rapid-fire exposures of a naked man jumping from one location to another? Each shot is effectively screened onto the other, lightening the film with each and every exposure. The photographer was smart enough to limit the exposure time so as not to overexpose the film; likewise, you should only apply Screen when working with images that are sufficiently dark so that you avoid overlightening. Figure 13-6: The Screen mode produces the same effect as shining two projectors at the same screen. It always results in a lighter image. ✦ Overlay (O), Soft Light (F), and Hard Light (H): You just can’t separate these guys. All three multiply the dark colors in the active layer and screen the light colors into the composite pixels in the layers below. But they apply their effects to different degrees. Overlay favors the composite pixels; Hard Light favors the layered pixels. (In fact, the two are direct opposites.) Soft Light is a washed-out version of Hard Light that results in a low-contrast effect. The left-hand examples in Figure 13-7 show a blend mode applied individually to the thinking fellow. I then duplicated the thinker layer with the blend mode still in force to get the effects on the right. As these examples demonstrate, the modes effectively tattoo one image onto the image behind it. Even after multiple applications of the thinker layer, the sunset image still shows through as if the thinker were appliquéd on.
618 Part IV ✦ Layers, Objects, and Text Overlay x2 Soft Light x2 Hard Light x2 Figure 13-7: The results of the Overlay, Soft Light, and Hard Light blend modes as they appear when applied to a single version of the thinker layer (left) and a second thinker layer (right).
Chapter 13 ✦ The Wonders of Blend Modes 619 Tip Start with the Overlay mode any time you want to mix both the active layer and the layers behind it to create a reciprocal blend. By a reciprocal blend, I mean a blend that mixes the colors evenly without eliminating any detail in either layer. After you apply Overlay, vary the Opacity to favor the composite pixels. I’ve said it before and I’ll say it again: Overlay is Photoshop’s most practical blend mode, the one you should always try first. If you can’t quite get the effect you want at lower Opacity settings, switch to the Soft Light mode and give that a try. On the other hand, if the Overlay mode at 100 percent seems too subtle, switch to Hard Light. You can even clone the layer to darn well emblazon the layer onto its background, as in the bottom-right image in Figure 13-7. ✦ Color Dodge (D): When you apply the Color Dodge mode, each color in the layer becomes a brightness-value multiplier. Light colors such as white pro- duce the greatest effect, and black produces no effect. As a result, Color Dodge is Photoshop’s most dramatic whitening agent, the equivalent of apply- ing bleach to colored fabric. When applied to the thinker in Figure 13-8, Color Dodge exaggerates the sunset, resulting in a rougher effect than either Screen or the upcoming Lighten. Figure 13-8: Color Dodge uses the active layer to bleach the pixels in the layer below. There is nothing subtle about this effect. ✦ Color Burn (B): If Color Dodge is bleach, then Color Burn is the charred sur- face of burnt toast. It uses the colors in the active layer to reduce brightness values, resulting in a radical darkening effect. Like Color Dodge, the Color Burn mode results in a radical, high-contrast effect, as shown in Figure 13-9. You may
620 Part IV ✦ Layers, Objects, and Text also want to sneak a peek at Color Plate 13-1, which illustrates how both Color Dodge and Color Burn sap the colors out of the active layer more surely than any other blend mode except Luminosity. If you want high-contrast stamping effects, these are the blend modes to use. Figure 13-9: Color Burn sears an image charcoal black. No other darkening mode is this severe. ✦ Darken (K): When you select this option, Photoshop applies colors in the active layer only if they are darker than the corresponding pixels below. Keep in mind that Photoshop compares the brightness levels of pixels in a full-color image on a channel-by-channel basis. So although the red component of a pixel in the active layer may be darker than the red component of the underly- ing composite pixel, the green and blue components may be lighter. In this case, Photoshop would assign the red component but not the green or blue, thereby subtracting some red and making the pixel slightly more turquoise. Compare the predictable grayscale example in Figure 13-10 to its more chal- lenging color counterpart in Color Plate 13-1. ✦ Lighten (G): If you select this option, Photoshop applies colors in the active layer only if they are lighter than the corresponding pixels in the underlying image. Again, Photoshop compares the brightness levels in all channels of a full-color image. Examples of the Lighten blend mode appear in Figure 13-11 and Color Plate 13-1.