Getting Four-Color Separations 659 Book IX Chapter 1 Prepping Graphics for Print Cyan Magenta Yellow Black Corbis Digital Stock Figure 1-2: Color images are separated into four process colors. Table 1-3 Output Options Option What It Does Recommendation Calibration Prints an 11-step grayscale bar out- Select this option. Bars side the image area to gauge how accurately the shades are being printed. When you’re printing sepa- rations, this option prints a gradient tint bar and color bar. Registration Prints crosshair and target marks Select this option. Marks outside the image area, allowing you to line up the four plates or pages. continued 660 Creating Spot Color Separations Table 1-3 (continued) Option What It Does Recommendation Corner Crop Adds crop marks at the corners of Select this option. Marks the image to indicate where to trim the image. Center Crop Adds crop marks at the center of Select this option. Marks each side of the image to indicate where to trim the image. Description Prints the description as entered in Select if you have the File➪File Info area. entered a description. Labels Prints the filename and channel Select this option. name on each plate or page. Emulsion Emulsion is the side of the film that’s Leave this option dese- Down light sensitive. Allows the film to lected for laser separa- be printed with the emulsion side tions. When the service down. bureau or offset printer prints the separations to film or plates, it may select this option. Negative Prints black as white and white as Leave this option dese- black, and every other color inverts lected for laser separa- accordingly. tions. When the service bureau or offset printer prints the separations to film or plates, it may select this option. Interpolation Anti-aliases low-resolution images Available only for by resampling. PostScript Level 2 or laser printers. Leave it deselected. Include See the “Saving and Printing Vector Leave this option Vector Data Data in a Raster File” section, in this selected if you have type chapter. or vector paths. Creating Spot Color Separations Photoshop allows you to add separate channels for spot colors (see Book VI, Chapter 1, for more on channels), which can then be color-separated. Spot, or custom, colors are premixed inks manufactured by various ink companies, the most popular in the U.S. being Pantone. A spot color is often used for a logo, type, or small illustration. Spot colors are also used when you need to Creating Spot Color Separations 661 apply metallic inks or varnishes to your print job. Spot colors can be used Book IX rather than, or in addition to, the four process CMYK colors. Chapter 1 If you’re delving into the world of spot colors, I highly recommend that Prepping Graphics you choose your color from a printed Pantone swatch book, available from for Print www.pantone.com. Because your screen is an RGB device and you’re set- ting up your file for a CMYK output device, the colors you see onscreen don’t match the colors that are ultimately on paper — at best, they’re a ballpark match. For accuracy, you must select the colors from the printed swatch book. For more on working with color, see Book II, Chapter 3. Creating a spot channel Follow these steps to create a spot channel: 1. On a separate layer, create the graphic or type to which you want to apply the spot color. 2. Ctrl-click (Ô-click on the Mac) the thumbnail of the layer to select the graphic and then choose Edit➪Fill to fill it with any solid color at an opacity of 100 percent. 3. With your selection active, choose Window➪Channels and then select New Spot Channel from the Channels panel pop-up menu. You can apply a spot color only to an active selection. It can’t be applied to just a layer. Figure 1-3: Adding an additional color separation in Photoshop requires creating a The New Spot Channel dialog box spot color channel first. appears, as shown in Figure 1-3. 4. In the Name text box, enter a name for your spot color. In the Ink Characteristics area, click the color swatch. I recommend naming your spot color according to the spot color you want to use, such as Pantone 7417C. When you click the color swatch, the Color Picker appears. 5. Click the Color Libraries button in the Color Picker and select your Pantone color from the Color Libraries dialog box that appears Figure 1-4: Select an appropriate color from (see Figure1-4), and then click OK. the Color Libraries dialog box. 662 Creating Spot Color Separations 6. In the New Spot Channel dialog box, select a Solidity value between 0 percent and 100 percent. A value of 100 percent represents an ink that’s completely opaque, such as a metallic ink, which completely covers the inks beneath it. A value of 0 percent represents a transparent ink, such as a clear varnish. But the solidity value affects only the screen view and com- posite prints; it doesn’t affect the separations. It can help you see where a “clear” varnish will print. Figure 1-5: The Channels panel displays the spot channel. 7. Click OK to close the dialog box. Your spot channel appears in the Channels panel and is filled in the image, as well. I created a spot channel for my crest graphic and for the type (Pantone 7417C), as shown in Figure 1-5. In the printing process, spot colors are overprinted on top of the four- color image, as shown in Figure 1-6. That means that the spot color is applied at the end of the printing process and is printed over the other inks. This can sometimes cause lighter spot colors to darken somewhat. If you need your spot color graphic to knock out the underlying image, create it in an illustration or page layout program. A knockout is a hole left in the four-color image, which is filled with the spot ink. Corbis Digital Stock The spot ink doesn’t print over the other inks. Figure 1-6: Spot colors are often used for color-critical logos that print on top of 8. Save the image in the native your image. Photoshop, Photoshop PDF, or Photoshop DCS 2.0 (Desktop Color Separations) format. TIFFs also support spot channels, but your page layout program may not recognize them. Creating Spot Color Separations 663 If the image is being separated directly out of Photoshop, leave it as a Book IX PSD or PDF file. If you want to import it into a different program, such as Chapter 1 InDesign, or QuarkXPress, you must save it as a DCS file. If your image is a duotone, tritone, or quadtone image, you also have to go through a few Prepping Graphics more hoops. You must first convert it to multichannel mode by choos- for Print ing Image➪Mode. In the DCS 2.0 Format dialog box, make sure that the Include Halftone Screen and Include Transfer options aren’t selected. Import the image into your destination application and set your screen angles. Editing a spot channel After you create a spot channel, you can edit it. Select the channel in the Channels panel and use a painting or editing tool to paint with black, white, or any shade of gray, just as you would with an alpha channel. To change any of the options of the spot channel, double-click the spot channel thumb- nail, or select it and then select Channel Options from the panel pop-up menu. Select a different color or solidity. Converting an alpha channel to a spot channel If you want to convert an alpha channel to a all areas containing nonwhite pixels (unselect- spot channel, select the alpha channel in the ed to partially selected areas) to the spot color. Channels panel and select Channel Options With the channel still selected in the Channels from the panel’s pop-up menu. Rename the panel, choose Image➪Adjustments➪Invert to channel and select Spot Color. Click the color apply the spot color to the white pixels or se- swatch and select a color from the Color Librar- lected areas of the alpha channel. For details ies section of the Color Picker. Click OK, then on alpha channels, see Book VI, Chapters 1 click OK again. Note that Photoshop converts and 3. 664 Book IX: Photoshop and Print Chapter 2: Using Photomerge and Merge to HDR Pro In This Chapter ✓ Creating a panorama from multiple shots ✓ Merging photos for superior quality S ometimes, working with just a single shot isn’t quite enough. You couldn’t quite squeeze that beautiful mountain vista into one photo; it took three shots. Not to worry, that’s what Photoshop’s Photomerge com- mand is for. This great command seamlessly stitches multiple shots of your panorama into a single image. Similarly, trying to capture the entire tonal range of an image can be tough. The Merge to HDR Pro command enables you to take multiple exposures of an image and later merge those exposures into a single High Dynamic Range image, allowing for superior image quality. And as if that alone isn’t enough, these two commands are found on Photoshop’s Automate menu, meaning they’re quite easy to use. Using the Photomerge Command The Photomerge command allows you to combine multiple images into one continuous panoramic image. For exam- ple, you can take several overlapping photos of a mountain range and put them together into one pan- oramic shot using the Photomerge dialog box, as shown in Figure 2-1. If you know you ultimately want to create a Photomerge composition, you can make things eas- ier by making sure that when you shoot your pho- tos, you overlap your individual images by 15 to 40 percent, but no more than 70 percent. Adobe also rec- ommends that you avoid using distortion lenses (such as fish-eye) and your camera’s zoom setting. Finally, try to stay in the same position and keep your camera at the same level for each shot. Using a tripod and rotating the head can help you achieve this consistency. If you are lucky enough to have a nice, long parallel surface handy (like a sidewalk), try taking spaced photos using your tripod along this surface. 666 Using the Photomerge Command Photodisc Figure 2-1: Select several overlapping shots to create one panoramic image. Follow these steps to assemble your own Photomerge composition: 1. Choose File➪Automate➪Photomerge. You can also select your desired source images and choose Tools➪ Photoshop➪Photomerge in Adobe Bridge. Using Bridge is a timesaver because you can quickly and visually select your images. 2. In the Photomerge dialog box, shown in Figure 2-1, select your source files. From the Use pop-up menu, you can select from Files (which uses indi- vidual files you select) or from Folder (which uses all images in a folder. Click the Add Open Files button to use all currently open files. Or click the Browse button to navigate to your desired files or folder. If you want to delete a file from the list, select it and click Remove. 3. Select Blend Images Together to correct the color differences that can occur from blending images with different exposures. Photoshop then blends the colors and tones. If the Blend Images Together option doesn’t help, you can always create a blending group. First, in your Layers panel, create a new group con- taining the layer you want to change. Next, change the group Blend mode to Normal. Finally, add an adjustment layer, such as Levels or Exposure, in the group above the layer you want to change. For more on Using the Photomerge Command 667 adjustment layers, see Book V, Chapter 1. For more on blend modes, see Book IX Book V, Chapter 3. Chapter 2 4. Select Vignette Removal to correct exposure problems caused by lens Using Photomerge vignetting (when light at the edges of images is reduced and therefore and Merge to HDR Pro edges are darkened). 5. Select Geometric Distortion Correction to correct for lens distortions, such as radial distortion, barrel distortion (bulging out), and pincush- ion distortion (pinching in). You can use this option to align shots taken with a fish-eye lens. 6. In the Layout area, select your desired project mode, as shown in Figure 2-1. The thumbnail illustration visually demonstrates each mode, but I’ll give you a little more description of each: • Auto: Select the Auto mode to make Photoshop analyze your images on its own. • Perspective: Select this mode if your images have been shot with per- spective, or at acute angles. This mode is also recommended for High Dynamic Range (HDR) images. • Cylindrical: Select this option if you shot your images with a wide- angle lens or when your images have that nasty “bow-tie” distortion. This mode is also good for those 360-degree, full panoramic shots. • Spherical: This mode is handy when stitching together a 360-degree panorama, in which you have a wide field of view, both horizontally and vertically. Use this option for shots taken with a wide-angle lens. • Collage: This projection method aligns images by rotating, position- ing, and uniformly scaling each image. It may be the best choice for pure panoramas, but you can also find it useful for stitching together images based on common features. • Reposition: When you select this mode, Photoshop doesn’t take into account any distortion, but merely scans the images and positions them in what it considers the best position. 7. Click OK. Photoshop marches off and attempts to automatically align and “stitch” your source images into a new Photoshop image, shown in Figure 2-2. Hopefully, all goes well; however, if Photoshop can’t align and merge, it presents an alert that says “some images could not be aligned.” No matter which projection mode you select, Photoshop leaves your merged image in layers. In addition to those layers, Photoshop may also add a layer mask to each layer to better blend and composite your merged image. These layer masks act like any other layer masks, meaning you can edit them to your liking. For more on layer masks, see Book VI, Chapter 3. 668 Using the Merge to HDR Pro Command Photodisc Figure 2-2: The Photomerge command enables you to combine multiple images into one continuous panoramic shot. Using the Merge to HDR Pro Command Have you ever caught an early matinee and emerged molelike from the pitch-black theater into the bright light of high noon, only to have to squint for a while because your eyes burned? Or on the flip side, have you blindly tumbled into your seat, popcorn scattering all over the aisle in that same darkened theater because you just came in from the bright daylight? In both cases, your eyes needed some time to adjust to the abrupt change from extreme dark to extreme light or vice versa. Cameras suffer from the same problem. But although our eyes can eventually adapt to varying brightness levels, cameras and devices, such as computer monitors and scanners, can capture only a fixed dynamic, or tonal, range. In digital imag- ing tech talk, dynamic range is the ratio of the darkest and brightest values a device can capture simultaneously. In the past, digital photography aficionados were hindered when performing higher-end, image-editing tasks in Photoshop because they were forced to work within a limited dynamic range. Recent versions of Photoshop have provided users with plenty of support for High Dynamic Range (HDR) images. HDR images, which contain 32 bits of data per channel, are superior to non- HDR images because they can capture a much larger dynamic range — in fact, they’re able to represent the entire dynamic range of the real world. Photographers can take multiple exposures of an image and then later merge those multiple exposures into a single photo in Photoshop, thereby captur- ing the entire dynamic range into a single HDR image. Although you can use the Merge to HDR Pro command on 8- or 16-bit images, be aware that only 32-bit images can store all the HDR data.
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