Photoshop Elements 15 For Dummies. Obermeier Barbara

other resample options above it.

In the drop-down list, you find different choices for resampling. See Table 2-2 for details on each method.

      When you select the Resample Image check box, the two check boxes above it become active. Here’s what they do:

      ● Scale Styles: Elements has a Styles panel from which you can add a variety of different style effects to images. (See Chapter 11 for details.) When you apply a style, such as a frame border, the border appears at a defined width. When you select the Scale Styles check box and then resize the image, the Styles effect is also resized. Leaving the check box deselected keeps the style at the same size while the image is resized.

      ● Constrain Proportions: By default, this check box is selected, and you should leave it that way unless you want to intentionally distort an image.

      5. When you’re done selecting your options, click OK to resize your image.

       FIGURE 2-2: The Image Size dialog box.

TABLE 2-2 Resampling Methods

       Understanding the results of resampling

       As a general rule, reducing resolution is okay, but increasing resolution isn’t. If you need a higher-resolution image and you can go back to the original source (such as rescanning the image or reshooting a picture), try (if you can) to create a new file that has the resolution you want instead of resampling in Elements. In some cases, upsampled images can be severely degraded. Regardless of whether you upsample or downsample an image, always save a copy of the photo under a new filename.

If you take a picture with a digital camera and want to add the picture to a web page, the image needs to be sampled at 72 ppi. In most cases, you visit the Image Size dialog box, select the Resample Image check box, add a width or height value, and type 72 in the Resolution text box. What you end up with is an image that looks great on your web page but still downloads quickly. In Figure 2-3, you can see an image that was downsampled in Elements from over 14 inches horizontal width.

       FIGURE 2-3: Downsampling images most often produces satisfactory results.

If you start with an image that was originally sampled for a web page and you want to print a large poster, you can forget about using Elements or any other image editor. Upsampling low-resolution images often turns them into the sort of mush shown in Figure 2-4.

       FIGURE 2-4: Upsampling low-resolution images often produces severely degraded results.

      You might wonder whether upsampling can be used for any purpose. In some cases, yes, you can upsample with some satisfactory results. You can achieve better results with higher resolutions of 300 ppi and more if the resample size isn’t extraordinary. If all else fails, try applying a filter to a grainy, upsampled image to mask the problem. Chapter 11 has the details on filters.

      Choosing a Resolution for Print or Onscreen

      The importance of resolution in your Elements work is paramount to printing files. Good ol’ 72-ppi images can be forgiving, and you can get many of your large files scrunched down to 72 ppi for websites and slideshows. For a nice-looking print, you need a much higher resolution. Many different printing output devices exist, and their resolution requirements vary.

      For your own desktop printer, plan to print a variety of test images at different resolutions and on different papers. You can quickly determine the best file attributes by running tests. When you send files to service centers, ask the technicians what file attributes work best with their equipment.

       White does not print as a color. When you use white, it appears transparent on your prints and the color appears the same as the paper color you’re using.

For a starting point, look over the recommended resolutions for various output devices listed in Table 2-3.

TABLE 2-3 Resolutions and Printing

       If all this is confusing, just leave it all up to the print driver to take care of the sampling.

      Go Ahead – Make My Mode!

      Regardless of what output you prepare your files for, you need to consider color mode and file format. In the section “Getting Familiar with Color” later in this chapter, we talk about RGB (red, green, and blue) color mode. You’ll likely use the RGB mode most of the time: RGB is what you use to prepare color files for printing on your desktop color printer or to prepare files for photo-service centers. It’s also the mode most commonly used for color images displayed onscreen.

      You can also use color modes other than RGB. If you start with an RGB color image, menu options in Elements enable you to convert to a different color mode. Photoshop Elements uses an algorithm (a mathematical formula) to convert pixels from one mode to another. In some cases, the conversion that’s made via a menu command produces good results, and in other cases, a method other than a menu command works better.

      In the following sections, we introduce the modes that are available in Elements, discuss when changing an image’s color mode can be useful, and explain how to convert from RGB to the mode of your choice: bitmap, grayscale, or indexed color.

       Another mode you may have heard of is CMYK. Although CMYK mode isn’t available in Photoshop Elements, you should be aware of what it is and the purposes of CMYK images. CMYK, commonly referred to as process color, contains percentages of cyan, magenta, yellow, and black colors. This mode is used for commercial printing. If you design a magazine cover in Elements and send the file to a print shop, the file is ultimately converted to CMYK. Also note that most desktop printers use different ink sets within the CMYK color space. CMYK is a narrower color space than RGB, which means there are fewer colors in CMYK. Therefore using CMYK inks on printers may often display some shifts in colors between the prints and the screen images.

       Converting to Bitmap mode

      Bitmap mode is most commonly used in printing line art, such as black-and-white logos, illustrations, or black-and-white effects that you create from your RGB images. Also, you can scan your analog signature as a bitmap image and import it into other programs, such as the Microsoft Office applications. If you’re creative, you can combine bitmap images with RGB color to produce interesting effects.

       When you combine images with different color modes into a single file, the images need to be in the same mode. (A file can have only one mode.) So, if you create an image in Bitmap mode and want to combine it with an RGB image, you need to convert the bitmap files to grayscale or color first. If you convert to grayscale, Elements takes care of converting grayscale to RGB mode.

As an example of an effect resulting from combining grayscale and color images, look over Figure 2-5. The original