Photoshop cs5 missing manual_2 ppt

215  :     Basic Channel Stunts Note: What’s the difference between “noise” and “grain”? They both describe tiny flecks on your image, but, technically speaking, noise occurs in digital images, whereas grain occurs in analog prints, film, and transparencies. In other words, grain becomes noise once you scan the image. However, let’s say you’re in RGB mode and you dutifully followed the instructions on page 462 and ran the Reduce Noise filter on your blue channel (which typically has the most noise, though sometimes noise can hide out in the red channel) and it didn’t do squat. What do you do? You can try bringing out some of the details in your image by sharpening only the red and green channels, as shown in Figure 5-15. Figure 5-14: Photoshop doesn’t let you merge two channels into one, but you can combine them into a new channel with the Calculations command: Choose Image➝Calculations and, in the dialog box shown here, set the Source 1 section’s Channel pop-up menu to “Red copy” and the Source 2 section’s menu to “Green copy”. Choose Multiply from the Blending pop-up menu at the bottom of the dialog box if you want to create a black object or Screen if you want to create a white one. When everything’s set, click OK. 216 P CS: T M M Basic Channel Stunts Tip: The next time you need to sharpen a portrait of someone who’s sensitive about his or her appear- ance, try sharpening only the red channel to avoid bringing out unwanted details in the person’s skin. (As you learned earlier in this chapter, most of the fine details live in the high-contrast green channel.) Here’s how to sharpen without making noise any worse than it already is: 1. Open your image and make a copy of the layer(s) you’re going to sharpen. If you’re working with a document that has just one layer, select it in your Layers panel and duplicate it by pressing �-J (Ctrl+J on a PC). If you like, double-click the layer’s name and rename it Sharpen. If you’re working on a multilayer document, press and hold the Option key (Alt on a PC) while choosing Merge Visible from the Layers panel’s menu (see the figure on page 78). Photoshop combines all the layers into a new layer. Drag this new layer to the top of your Layers panel and name it Sharpen. Figure 5-15: If you select the red and green channels before running a sharpening filter, you restrict the sharpening to those channels. That helps you avoid sharpening, and therefore accentuating, any noise. 2. Open the Channels panel (page 189) and select the red and green channels. Click to select one channel and then Shift-click to select the other one, so they’re both highlighted in your Channels panel. Don’t panic if your image turns a weird color (like the horse in Figure 5-15); Photoshop is just showing you the image using only those two color channels. 217  :     Basic Channel Stunts 3. Choose Filter➝Sharpen➝Unsharp Mask (page 463). When you run a filter while you’ve got only certain channels selected, Photo- shop applies the sharpening to just those channels. In this case, it won’t apply any sharpening to the blue channel. Click OK to close the Unsharp Mask dialog box. 4. In the Channels panel, turn on the composite channel (here, that’s RGB) to see your new and improved full-color image. You’re done! If you want to see before and after versions of your image, open the Layers panel and toggle the Sharpen layer’s visibility eye (page 82) off and on. Tip: Another, more advanced way to sharpen your image is to use the channel with the highest contrast to create an intricate edge mask. You can read all about that process on page 475. [...]... save them in Photoshop format, you can tell Camera Raw to preserve the cropped pixels in case you want to resurrect them later (see Figure 6-13 for details) • The Open Images button to apply the changes and open the photo(s) in Photoshop 234 Photoshop CS5: The Missing Manual Cropping Images Figure 6-12:  Open one or more images in Camera Raw and use the Crop tool just like you would in Photoshop (Remember,... the granddaddy of Photoshop principles: Image Resolution—the measurement that determines the size of the pixels in your image, which in turn controls the quality of your prints 236 Photoshop CS5: The Missing Manual Resizing Images Figure 6-14:  Top: Camera Raw can’t take a document full of images and then crop, straighten, and split them out into individual documents automatically like Photoshop (page... 248 Photoshop CS5: The Missing Manual Resizing Images 3 To keep the photo’s quality relatively intact while you reduce the file size, choose High from the Compression Quality pop-up menu (also circled in Figure 6-20, upper right) To make the file smaller, Photoshop throws away image details and then compresses what’s left If you set the quality level to High (which has a numeric equivalent of 60), Photoshop. .. (see Chapter 3) Just select the layer of the image you want to extract, run the command, and Photoshop strips that layer out into its own document and deletes it from the original document If that layer contains several images, they’ll get stripped out into their own individual documents 232 Photoshop CS5: The Missing Manual Cropping Images Figure 6-11:  It’s tough to get a bunch of photos perfectly... image quality Resampling is a process in which Photoshop responds to your size-change request either by adding or subtracting pixels The problem, as you’ll learn in a moment, is that resampling involves guesswork on Photoshop s part, which can obliterate image quality When you first launch Photoshop, the Resample Image setting is turned on, which tells Photoshop to increase or decrease the number of... 57) When this happens, breathe deeply, smile smugly, and proceed to Table 6-1 on page 243 Or just click the Auto button in the Image Size dialog box and let Photoshop figure out the ppi from lpi for you, as Figure 6-17 explains Photoshop CS5: The Missing Manual Resizing Images Resolution guidelines for print Now that you understand what resolution is and how it works, the question becomes how much resolution... third-party plug-ins Photoshop CS5: The Missing Manual Resizing Images Resizing your images is a snap, but the risk of reducing image quality in the process is high As you learned in the previous section, the key to preserving quality lies in turning on the Resample Image checkbox shown in Figure 6-18 Note: If you’re printing a generic-size image (like 8"×10" or 5"×7") straight from Photoshop, you can... final result, you’ll also need to enter a resolution (page 238); otherwise, you can leave this box blank 226 Photoshop CS5: The Missing Manual Cropping Images Note: When you enter a custom crop size, be sure to include a unit of measurement, such as px for pixels or in for inches Otherwise, Photoshop assumes you mean the unit of measurement that’s set in your preferences, which may not be what you... drag its bottom-right corner until you’ve got a few inches of gray space on all four sides of your image This bit of window resizing makes it easier to see what you’re doing in the next step 228 Photoshop CS5: The Missing Manual Cropping Images Figure 6-9:  Left: To create the look of a Polaroid, use the Crop tool (page 222) to add canvas space around your photo as shown here Be sure to add a little extra... resizing, and rotating 235 Resizing Images Figure 6-13:  To see and work with your original, pre-cropped image in Photoshop, click Camera Raw’s Save Images button, choose Photoshop from the Format pop-up menu, and then turn on the Preserve Cropped Pixels checkbox Next time you open that file in Photoshop, the photo appears on its own layer If you want to see the hidden, cropped bits, use the Move tool to . sounds—just take a look at Figure 6 -2. Note: In Photoshop CS5, the Crop tool actually comes with a rule-of-thirds grid, making this rule easier than ever to grasp and follow! 22 1  : , ,. doing in the next step. 22 9  : , ,   Cropping Images Figure 6-9: Left: To create the look of a Polaroid, use the Crop tool (page 22 2) to add canvas space. (page 27 ). Better yet, if you like the crop but want to make sure you keep a copy of the original, uncropped version, go to File➝Save As right after you crop the photo and give it a new name. 22 4 P