Photoshop Elements 2022 For Dummies. Barbara Obermeier
need to exercise some caution when you’re using the JPEG format. JPEG files are compressed to reduce file size, so you can scrunch an image of several megabytes into a few hundred kilobytes. When you save a file with JPEG compression, however, you experience data loss. You might not see this on your monitor, or it might not appear noticeably on photo prints if you’re using low compression while preserving higher quality. However, when you save with maximum compression, more pixels are tossed away, and you definitely notice image degradation.
When you select JPEG for the format and click Save, the JPEG Options dialog box opens, as shown in Figure 2-4. You choose the amount of compression by typing a value in the Quality text box or by moving the slider below the Quality text box. The acceptable range is from 0 to 12 — 0 is the lowest quality and results in the highest compression, and 12 is the highest quality and results in the lowest amount of compression.
Notice that you also have choices in the Format Options area of the JPEG Options dialog box. The Progressive option creates a progressive JPEG file commonly used with web browsers. This file type shows progressive quality while the file downloads from a website. The image first appears in a low-quality view and shows higher-resolution views until the image appears at full resolution when it’s completely downloaded in your browser window.
FIGURE 2-4: When saving in JPEG format, choose the amount of compression you want to apply to the saved image.
PNG (*.png)
PNG (Portable Network Graphics) is another format used with web pages. PNG supports all color modes, 24-bit images, and transparency. One disadvantage of using PNG is that color profiles can’t be embedded in the images, as they can with JPEG. An advantage, however, is that PNG uses lossless compression, resulting in images without degradation.
PNG is also an option in the Save for Web dialog box. Choose File ⇒ Save for Web to export your photos as PNG.
TIFF (*.tif, *.tiff)
TIFF (Tagged Image File Format) is the most common format used by graphic designers. TIFF is generally used for importing images in professional layout programs, such as Adobe InDesign and QuarkXPress, and when commercial photo labs and print shops use equipment that supports downloading TIFF files directly to their devices. (Note: Direct downloads are used in lieu of opening a Print dialog box.)
Inasmuch as creative professionals have used TIFF for so long, a better choice for designers using a program such as Adobe InDesign is to save in the native Photoshop PSD file format. This requires a creative professional to save only one file in native format without bothering to save both native and TIFF formats.
TIFF, along with Photoshop PSD and Photoshop PDF, supports saving layered files and works in all color modes. When you save in TIFF, you can also compress files in several different compression schemes, but compression with TIFF files doesn’t lose data unless you choose a JPEG compression.
When you choose TIFF from the Format drop-down list and click Save in the Save/Save As dialog box, the TIFF Options dialog box opens. Your options for image compression include
NONE: Selecting this option results in no compression. You use this option when sending files to creative professionals for creating layouts in programs such as Adobe InDesign. (None of the three compression schemes listed next is recommended for printing files to commercial printing devices.)
LZW: This lossless compression scheme results in much lower file sizes without destroying data.
ZIP: ZIP is also a lossless compression scheme. You can favor ZIP compression over LZW when you have large areas of the same color in an image.
JPEG: JPEG is lossy and results in the smallest file sizes. Use JPEG here the same as when you apply JPEG compression with files saved in the JPEG format.
Leave the remaining items in the dialog box at defaults and click OK to save the image.
Getting Familiar with Color
In this section, you find some fundamental principles to make your work in Elements easier when you’re editing color images.
When you see a color pixel (a tiny square), the color is represented as different levels of gray in each channel. This may sound confusing at first, but stay with us for just a minute. When you have a color channel, such as the red channel, and you let all light pass through the channel, you end up with a bright red. If you screen that light a little with a gray filter, you let less light pass through, thereby diluting the red color. This is how channels work. Individually, they all use different levels of gray that permit up to 256 levels of light to pass through them. When you change the intensity of light in the different channels, you ultimately change the color.
Each channel can have up to 256 levels of gray that mask out light. The total number of possibilities for creating color in an RGB model is achieved by multiplying the values for each channel (256 × 256 × 256). The result is more than 16.7 million; that’s the total number of colors a computer monitor can display in RGB color.
This is all well and good as far as theory goes, but what does that mean in practical terms? Actually, you see some of this information in Elements’ tools and dialog boxes. As an experiment, open a file in Elements and choose Enhance ⇒ Adjust Lighting ⇒ Levels; the Levels dialog box shown in Figure 2-5 opens.
FIGURE 2-5: The Levels dialog box.
Notice that the Channel drop-down list shows you Red, Green, and Blue as individual channels, as well as a composite RGB selection. Furthermore, the Output Levels area shows you values ranging from 0 on the left to 255 on the right. Considering that 0 is a number, you have a total of 256 different levels of gray.