Switching to the Mac: The Missing Manual, El Capitan Edition

Graphics in OS X

Everywhere you look in OS X, you’ll find visual effects that would make any other operating system think about early retirement.

For example: Menus are transparent. You can set Excel 3D graphs to be slightly transparent so they don’t block other bars in a 3D graph. When you paste files into windows in icon view, their icons fade into view. When you open an especially long message in Mail, its text fades in from white. When you use Launchpad, it fades in and out. And when you switch accounts using fast user switching, your work environment slides off the screen as though it’s pasted on the side of an animated cube.

All these visual goodies owe their existence to Quartz (or its enhanced successor, Quartz Extreme, which is not available on older Macs).

Graphics Formats on the Mac

OS X understands dozens of Mac and Windows graphics file formats. Better yet, its Preview program can open such graphics and export them in a different format, making it an excellent file-conversion program. You can confidently double-click graphics files—from a digital camera, scanner, or web download, for example—in any of these formats:

• PICT files. For almost 20 years, the PICT file was the graphics format Mac fans were most familiar with. It was the graphics format used by the Mac Clipboard, and it was the format created by the Shift-⌘-3 keystroke (see Screen-Capture Keystrokes). Unfortunately, no other kinds of computers could open these files. The Preview program can no longer save graphics in the PICT format. It can open them, but only when it’s running in 32-bit mode.

• TIFF files. The TIFF file format is a high-density, high-quality, uncompressed bitmap—that is, the Mac has memorized the color of each tiny dot in the file. Trying to enlarge one is like enlarging a fax: Make it too big, and the image breaks down into visible dots.

  UP TO SPEED: The Color Picker

  Here and there—in System Preferences, iMovie, TextEdit, Microsoft Office, and many other programs—OS X offers you the opportunity to choose a color for some element: for your desktop background, a window, and so on.

  The dialog box that appears offers a miniature color lab that lets you dial in any color in the Mac rainbow—several color labs, actually, arrayed across the top, each designed to make color choosing easier in certain circumstances:

  Color wheel. Drag the scroll bar vertically to adjust the brightness, and then drag your cursor around the ball to pick the shade.

  Color sliders. From the pop-up menu, choose the color-mixing method you prefer. CMYK stands for cyan, magenta, yellow, and black. People in the printing industry will feel immediately at home, because these four colors are the component inks for color printing. (These people may also be able to explain why K stands for black.)

  RGB is how a TV or computer monitor thinks of colors: as proportions of red, green, and blue light. Grayscale means shades of gray, like a black-and-white TV. And HSB stands for hue, saturation, and brightness—a favorite color-specifying scheme in scientific circles.

  In each case, just drag the sliders to mix up the color you want, or type in the percentages of each component.

  Color palettes. This option presents sets of color swatches. They’re primarily for programmers who want quick access to the standard colors in OS X. The Web Safe Colors list is useful for web designers, too; they can use it to ensure that the colors they choose will display properly on other computers.

  

  Image palettes. Here’s the visible rainbow arrayed yet another way: in cloudy, color-arranged streaks. (Cool tip: If you drag a graphics file directly into the dialog box, it appears in the spectrum’s place. That’s a handy trick if you’re trying to identify the color of a certain spot of an image, for example. And don’t miss the pop-up button at the bottom of the dialog box, which offers a few other stunts.)

  Crayons. Now this is a good user interface. You can click each crayon to see its color name: Mocha, Fern, Cayenne, and so on. (Some interior decorator in Cupertino had a field day naming these crayons.)

  In any of these color pickers, you can also “sample” a color that’s outside the dialog box—a color you found on a web page, for example. Just click the magnifying-glass icon and then move your cursor around the screen. You’ll see the sliders and numbers change inside the dialog box automatically when you click.

  Finally, note that you can store frequently used (or frequently admired) colors in the tiny palette squares at the bottom. To do that, drag the big rectangular color swatch (next to the magnifying glass) directly down into one of the little squares, where it will stay fresh for weeks.

  If you don’t have space for all the colors you want at the bottom of the window, you can drag the small dot down to make room for more.

  Nonetheless, TIFF files are very popular in the printing industry—the graphics in this book, for example, were stored as TIFF files. They print beautifully, work nicely in page-layout programs, and are understood by both Macs and Windows PCs. (They’re also pretty big files.)

• JPEG files. This format is one of the most popular on the web, particularly for photos or other high-quality, full-color artwork. What makes JPEG files ideal for online use is that they’ve been compressed (using a program like Photoshop). Just enough of the color data has been thrown out from the original file to make the image a quick download without noticeably affecting its quality.

• GIF files. GIF stands for graphics interchange format. Today, GIF files are used almost exclusively on the web, usually for solid-colored graphics like cartoons, headlines, and logos. (A GIF file can have a maximum of 256 colors, which is not even close to the photorealism of, say, JPEG. That’s what makes the GIF format inappropriate for photographs.)

• PNG files. As it turns out, one of the algorithms used by GIF files is, technically speaking, the property of a company called Unisys, which threatened to sue everybody who was creating GIF files. “No problem,” said the World Wide Web Consortium. “We’ll just come up with our own replacement—a file format that has no legal strings attached.” What they created was PNG (Portable Network Graphics). You can save Photoshop and Preview documents in PNG format, and every modern web browser understands it. Screenshots you take in OS X are in PNG, too.

  PNG files don’t lose quality when compressed, as JPEG files do. On the other hand, PNG files don’t accommodate animation, as GIF files do. And when it comes to photos, they don’t offer as impressive a size/quality balance as JPEG.

• Photoshop files. If you’re a graphic designer or webmeister, this one is kind of neat: OS X can open (and Preview can even export) actual Photoshop files (except for so-called 16-bit RGB files). In practical terms, the fact that OS X can open and display these files means that you could use a Photoshop masterpiece, complete with layers and transparency, as, for example, an OS X desktop background.

• BMP files. You can think of this graphics format as the PICT of the Windows world. It’s nice that OS X can open (and Preview can export) them, especially because you may occasionally find .bmp files on the web or attached to email messages.

• Silicon Graphics, MacPaint, Targ. You could go your whole life without ever seeing a graphic in one of these formats. Silicon Graphics is, unsurprisingly, the format created by Silicon Graphics computers. MacPaint is a black-and-white, 8x10–inch maximum, ancient Macintosh graphics format that disappeared from the scene in about 1988. And Targ (Targa) is the format once used by products from Truevision.