Photoshop 6 for Windows Bible- P27 potx

753 Chapter 16 ✦ Essential Color Management If you’re saving the profile from Photoshop 6, choose Edit ➪ Color Settings, and then choose Save CMYK from the CMYK pop-up menu and give the file a name. Wait to click Save until the next step. 2. Save the ICM file to the Recommended folder. For Photoshop 6 to see the CMYK profile, you have to save it to a specific folder. The path for that folder is C:\Program Files\Common Files\Adobe\Color\Profiles\Recommended. This means you open the Program Files folder, then the Common Files folder, then Adobe, then Color, then Profiles, and then Recommended. When you finally arrive inside the Recommended folder, save the ICM file. 3. Quit Photoshop. Regardless of which version of Photoshop you’re using, quit it by choosing File ➪ Exit. 4. Launch Photoshop 6. By starting (or restarting) Photoshop 6, you force the program to load the ICM profile. 5. Confirm the profile has loaded. Choose Edit ➪ Color Settings and click the CMYK pop-up menu in the Working Spaces area. You should see the profile you saved in the menu. Because the ICM file created in the previous steps resides in the Recommended folder, it appears in the CMYK pop-up menu even when the Advanced Mode check box is turned off. Any ICM files saved in the Profiles folder but outside the Recommended folder appear only when Advanced Mode is turned on. ✦✦✦ Tip Mapping and Adjusting Colors What Is Color Mapping? Color mapping is just a fancy name for shuffling colors around. For example, to map Color A to Color B simply means to take all the A-colored pixels and convert them to B-colored pixels. Photoshop provides several commands that enable you to map entire ranges of colors based on their hues, saturation levels, and most frequently, brightness values. Color effects and adjustments Why would you want to change colors around? For one thing, to achieve special effects. You know those psychedelic horror movies that show some guy’s hair turning blue while his face turns purple and the palms of his hands glow a sort of corn- flower yellow? No? Funny, me neither. But a grayscale version of this very effect appears in the second example of Figure 17-1. Although not the most attractive effect by modern stan- dards—you may be able to harvest more tasteful results if you put your shoulder to the color wheel — psychedelic quali- fies as color mapping for the simple reason that each color shifts incrementally to a new color. But the more common reason to map colors is to enhance the appearance of a scanned image or digital photograph, as demonstrated in the third example in Figure 17-1. In this case, you’re not creating special effects; you’re just making straightforward repairs, alternatively known as color adjustments, or corrections. Scans are never perfect, no matter how much money you spend on a scanning device or a service bureau. They can always benefit from tweaking and subtle adjustments, if not outright overhauls, in the color department. 17 17 CHAPTER ✦✦✦✦ In This Chapter Mapping colors with Invert, Equalize, Threshold, and Posterize Converting a selected area to grayscale Rotating colors around the color wheel using Hue/Saturation Raising and lowering saturation levels Colorizing grayscale images Correcting colors with Replace Color, Selective Color, and Variations Increasing the saturation of a heavily compressed image Boosting brightness and contrast levels Editing specific color values with Curves Applying gradient maps Correcting multiple layers at once with adjustment layers ✦✦✦✦ 756 Part V ✦ Color for Print and the Web Figure 17-1: Nobody’s perfect, and neither is the best of scanned photos (left). You can modify colors in an image to achieve special effects (middle) or simply fix the image with a few well-targeted color corrections (right). Too bad Photoshop hasn’t delivered on its promised Remove Excessive Jewelry filter. Keep in mind, however, that Photoshop can’t make something from nothing. In creating the illusion of more and better colors, most of the color-adjustment operations that you perform actually take some small amount of color away from the image. Somewhere in your image, two pixels that were two different colors before you started the correction change to the same color. The image may look 10 times better, but it will in fact be less colorful than when you started. It’s important to remember this principle because it demonstrates that color mapping is a balancing act. The first nine operations you perform may make an image look progressively better, but the tenth may send it into decline. There’s no magic formula; the amount of color mapping you need to apply varies from image to image. But if you follow my usual recommendations—use the commands in moder- ation, know when to stop, and save your image to disk before doing anything drastic — you should be fine. The good, the bad, and the wacky Photoshop stores all of its color mapping commands under the Image➪ Adjust submenu. These commands fall into three basic categories: ✦ Color mappers: Commands such as Invert and Threshold are quick-and-dirty color mappers. They don’t correct images, but they can be useful for creating special effects and adjusting masks. 757 Chapter 17 ✦ Mapping and Adjusting Colors ✦ Easy color correctors: Brightness/Contrast and Color Balance are true color correction commands, but they sacrifice functionality for ease of use. If I had my way, these commands would be removed from the Image ➪ Adjust submenu and thrown in the dust heap. ✦ Expert color correctors: The third, more complicated variety of color correction commands provides better control, but they take a fair amount of effort to learn. Levels, Curves, and Hue/Saturation are examples of color correcting at its best and most complicated. This chapter contains little information about the second category of commands for the simple reason that some of them are inadequate and ultimately a big waste of time. There are exceptions, of course —Auto Levels and Auto Contrast are decent quick fixers, and Variations offers deceptively straightforward sophistication —but Brightness/Contrast and Color Balance sacrifice accuracy in their attempt to be straightforward. They are as liable to damage your image as to correct it, making them dangerous in a dull, pedestrian sort of way. I know because I spent my first year with Photoshop relying exclusively on Brightness/Contrast and Color Balance, all the while wondering why I couldn’t achieve the effects I wanted. Then, one happy day, I spent about half an hour learning Levels and Curves, and the quality of my images skyrocketed. So wouldn’t you just rather learn it correctly in the first place? I hope so, because that’s what we’re all about to do. Quick Color Effects Before we get into all the high-end gunk, however, I take a moment to explain the first category of commands, all of which happen to occupy one of the lower sections in the Image ➪ Adjust submenu. These commands— Invert, Equalize, Threshold, and Posterize —produce immediate effects that are either difficult or require too much effort to duplicate with the more full-featured commands. Invert When you choose Image ➪ Adjust➪ Invert (Ctrl+I), Photoshop converts every color in your image to its exact opposite, as in a photographic negative. As demonstrated in Figure 17-2, black becomes white, white becomes black, fire becomes water, good becomes evil, dogs romance cats, and the brightness value of every primary color component changes to 255 minus the original brightness value. By itself, the Invert command is not sufficient to convert a scanned color photographic negative to a positive. Negative film produces an orange cast that the Invert command does not address. After inverting, you can use the Variations command to remove the color cast. Or avoid Invert altogether and use the Levels command to invert the image. Both Variations and Levels are explained later in this chapter. Note 758 Part V ✦ Color for Print and the Web Figure 17-2: An image before the advent of the Invert command (left) and after (right). Image ➪ Adjust➪ Invert is just about the only color mapping command that retains the rich diversity of color in an image. (The Hue/Saturation command also retains color diversity under specific conditions.) For example, if you apply the Invert command twice in a row, you arrive at your original image without any loss in quality. When you’re working on a full-color image, the Invert command simply inverts the contents of each color channel. This means the command produces very different results when applied to RGB, Lab, and especially CMYK images. Color Plate 17-1 shows the results of inverting a single image in each of these modes. The RGB and Lab images share some similarities, but you’ll find all kinds of subtle differences if you study the backgrounds and the basic colors of the faces. Inverting in CMYK is much different. Typically, the Invert command changes most pixels in a CMYK image to black. Except in rare instances— such as in night scenes— the black channel contains lots of light shades and few dark shades. So when you invert the channel, it becomes extremely dark. To reverse this effect, I inverted only the cyan, magenta, and yellow channels in the right example of Color Plate 17-1. (I did this by inverting the entire image and then going to the black channel —Ctrl+4 —and pressing Ctrl+I again.) Although this approach is preferable to inverting the black channel, it prevents the blacks in the hair and shadows from turning white (which would be the only portions even remotely light had I inverted the black channel as well). Just so you know, when I refer to applying color corrections in the CMYK mode, I mean applying them after choosing Mode ➪ CMYK Color. Applying corrections in the RGB mode when View➪ Preview ➪ CMYK is active produces the same effect as when CMYK Preview is not selected; the only difference is that the on-screen colors are curtailed slightly to fit inside the CMYK color space. You’re still editing inside the same old red, green, and blue color channels, so the effects are the same. Note Original Invert 759 Chapter 17 ✦ Mapping and Adjusting Colors As I mentioned back in Chapter 12, inverting the contents of the mask channel is the same as applying Select ➪ Inverse to a selection outline in the marching ants mode. In fact, this is one of the most useful applications of the filter. If you’re considering inverting a color image, however, I strongly urge you to try out the SuperInvert filter in the Tormentia folder on the CD at the back of this book. It permits you to invert each channel independently and incrementally. Any setting under 128 lessens the contrast of the channel; 128 makes it completely gray; and any value over 128 inverts it to some degree. Equalize Equalize is the smartest and at the same time least useful of the Image ➪ Adjust pack. When you invoke this command, Photoshop searches for the lightest and darkest color values in a selection. Then it maps the lightest color in all the color channels to white, maps the darkest color in the channels to black, and distributes the remaining colors to other brightness levels in an effort to evenly distribute pixels over the entire brightness spectrum. This doesn’t mean that any one pixel will actually appear white or black after you apply Equalize; rather, one pixel in at least one channel will be white and another pixel in at least one channel will be black. In an RGB image, for example, the red, green, or blue component of one pixel would be white, but the other two components of that same pixel might be black. The result is a higher contrast image with white and black pixels scattered throughout the color channels. If no portion of the image is selected when you choose Image ➪ Adjust ➪ Equalize, Photoshop automatically maps the entire image across the brightness spectrum, as shown in the upper-right example of Figure 17-3. If you select a portion of the image before choosing the Equalize command, however, Photoshop displays a dialog box containing the following two radio buttons: ✦ Selected Area Only: Select this option to apply the Equalize command strictly within the confines of the selection. The lightest pixel in the selection becomes white, the darkest pixel becomes black, and the others remap to shades in between. ✦ Entire Image Based on Area: If you select the second radio button, which is the default setting, Photoshop applies the Equalize command to the entire image based on the lightest and darkest colors in the selection. All colors in the image that are lighter than the lightest color in the selection become white and all colors darker than the darkest color in the selection become black. The bottom two examples in Figure 17-3 show the effects of selecting different parts of the image when the Entire Image Based on Area option is in force. In the left example, I selected a dark portion of the image, which resulted in over-lightening of the entire image. In the right example, I selected an area with both light and dark values, which boosted the amount of contrast between highlights and shadows in the image. Cross- Reference 760 Part V ✦ Color for Print and the Web Figure 17-3: An image before (top left) and after (top right) applying the Equalize command when no portion of the image is selected. You can also use the brightness values in a selected region as the basis for equalizing an entire image (bottom left and right). The problem with the Equalize command is that it relies too heavily on some bizarre automation to be of much use as a color correction tool. Certainly, you can create some interesting special effects. But if you’d prefer to automatically adjust the colors in an image from black to white regardless of the color mode and composition of the individual channels, choose Image ➪ Adjust ➪ Auto Levels (Ctrl+Shift+L). If you want to adjust the tonal balance manually and therefore with a higher degree of accuracy, the Levels and Curves commands are tops. I explain all these commands at length later in this chapter. Original Equalize all Equalize based on selection 761 Chapter 17 ✦ Mapping and Adjusting Colors Threshold I touched on the Threshold command a couple of times in previous chapters. As you may recall, Threshold converts all colors to either black or white, based on their brightness values. When you choose Image ➪ Adjust➪ Threshold, Photoshop displays the Threshold dialog box shown in Figure 17-4. The dialog box offers a single option box and a slider bar, either of which you can use to specify the medium brightness value in the image. Photoshop changes any color lighter than the value in the Threshold option box to white and changes any color darker than the value to black. Figure 17-4: The histogram in the Threshold dialog box shows the distribution of brightness values in the selection. The dialog box also includes a graph of all the colors in the image — even if only a portion of the image is selected. This graph is called a histogram. The width of the histogram represents all 256 possible brightness values, starting at black on the left and progressing through white on the right. The height of each vertical line in the graph demonstrates the number of pixels currently associated with that brightness value. Therefore, you can use the histogram to gauge the distribution of lights and darks in your image. It may seem weird at first, but with enough experience, the histogram becomes an invaluable tool, permitting you to corroborate the colors that you see on-screen. Generally speaking, you achieve the best effects if you change an equal number of pixels to black as you change to white (and vice versa). So rather than moving the slider bar to 128, which is the medium brightness value, move it to the point at which the area of the vertical lines to the left of the slider triangle looks roughly equivalent to the area of the vertical lines to the right of the slider triangle. The upper-left example in Figure 17-5 shows the result of applying the Threshold command with a Threshold Level value of 128 (as in Figure 17-4). Although this value evenly distributes black and white pixels, I lost a lot of detail in the dark areas. Tip Histogram 762 Part V ✦ Color for Print and the Web Figure 17-5: By itself, the Threshold command tends to deliver flat results (top left). To better articulate the detail, apply High Pass and other filters before choosing Threshold. As you may recall from my “Using the High Pass filter” discussion in Chapter 10, you can use Filter ➪ Other ➪ High Pass before you use the Threshold command to retain areas of contrast. In the upper-right image in Figure 17-5, I applied the High Pass filter with a radius of 1.0 pixel, followed by the Threshold command with a value of 125. In the two bottom images, I first chose an effects filter —Filter ➪ Artistic ➪ Watercolor on the left and Filter ➪ Sketch ➪ Bas Relief on the right — and then I applied High Pass with a radius of 1.0 pixel followed by the Threshold command. Threshold only High Pass first Watercolor and High Pass Bas Relief and High Pass [...]... 17 -6 shows all the effects from Figure 17-5 applied to layers subject to the Overlay blend mode and 50 percent Opacity In each example, the translucent selection helps to add contrast and reinforce details in the original image Photoshop Figure 17 -6: The Threshold operations from Figure 17-5 applied to separate layers, blended with the Overlay mode and an Opacity value of 50 percent 6 Photoshop 6 adds... colors using Image ➪ Mode ➪ Indexed Colors and save the final image in the GIF format for use on the Web (as I discuss in Chapter 19) 765 766 Part V ✦ Color for Print and the Web But mostly, you’ll use Desaturate to rob color from discrete selections or independent layers, neither of which the Grayscale mode can accommodate For example, in Color Plate 17-4, I used Select ➪ Color Range to select all of... of 50 percent 6 Photoshop 6 adds a new method for speeding up screen previews Press Ctrl+K, press Ctrl+3, and turn on the Pixel Doubling check box From now on, whenever you’re working in a color correction dialog box, Photoshop will double up pixels so long as you’re moving a slider Release the slider, and the other pixels fill in 763 764 Part V ✦ Color for Print and the Web If you want to achieve a... Auto Levels is that it modifies values on a channel-by-channel basis, which means it has a habit of upsetting the balance of colors in an image Consider Color Plate 17 -6, for example The first image is severely 767 768 Part V ✦ Color for Print and the Web washed out Choosing the Auto Levels command results in a bolder and more vibrant image, but it also changes the cast from sienna to burgundy The solution... of colors (bottom) 769 770 Part V ✦ Color for Print and the Web Note When the Colorize check box is selected, Hue becomes an absolute value measured from 0 to 360 degrees A Hue value of 0 is red, 30 is orange, and so on, as described in Chapter 4 ✦ Saturation: The Saturation value changes the intensity of the colors Normally, the Saturation value varies from –100 for gray to +100 for incredibly vivid... retaining the core brightness information from the original image This command is perfect for colorizing grayscale images I know, I know, Woody Allen wouldn’t approve, but with some effort, you can make Ted Turner green with envy Just scan him and change the Hue value to 140 degrees Chapter 17 ✦ Mapping and Adjusting Colors When you choose Image ➪ Adjust ➪ Hue/Saturation (Ctrl+U), Photoshop displays the Hue/Saturation... equivalent — Ctrl+1 for Reds, Ctrl+2 for Yellows, and so on Each of the Edit options isolates a predefined range of colors inside the image For example, the Reds option selects the range measured from 345 to 15 degrees on the Hue wheel Naturally, if you were to modify just the red pixels and left all non-red pixels unchanged, you’d end up with some jagged transitions in your image So Photoshop softens... display the Info palette (F8) before choosing the Hue/Saturation command Then move the cursor inside the image window As shown in Figure 17-11, the Info palette tracks the individual RGB and CMYK values of the pixel beneath the cursor The number before the slash is the value before the color adjustment; the number after the slash is the value after the adjustment Before After Figure 17-11: When you... box, shown in Figure 17-9 Before I explain how to use this dialog box to produce specific effects, let me briefly introduce the options, starting with the three option boxes: ✦ Hue: The Hue slider bar measures colors on the 360 -degree color circle, as explained back in the “HSB” section of Chapter 4 You can adjust the Hue value from negative to positive 180 degrees As you do, Photoshop rotates the colors... a drab and murky image But when I applied Auto Levels, Photoshop pumped up the lights Chapter 17 ✦ Mapping and Adjusting Colors and darks, bolstering the contrast Although I would argue that the corrected image is too dark, it’s not half bad for an automated, no-brainer command that you just choose and let rip Figure 17-8: A grayscale image before (left) and after (right) applying the Auto Levels command . file. 3. Quit Photoshop. Regardless of which version of Photoshop you’re using, quit it by choosing File ➪ Exit. 4. Launch Photoshop 6. By starting (or restarting) Photoshop 6, you force the program. correction dialog box, Photoshop will double up pixels so long as you’re moving a slider. Release the slider, and the other pixels fill in. 6 Photoshop 6 764 Part V ✦ Color for Print and the Web If. Colors and save the final image in the GIF format for use on the Web (as I discuss in Chapter 19). Posterize High Pass first 766 Part V ✦ Color for Print and the Web But mostly, you’ll use