Computer Beginner Guide

The four sets of option boxes inside the Color Picker dialog box represent color models or, if you prefer, color modes (one less letter, no less meaning, perfect for you folks who are trying to cut down in life). Color models are different ways to define colors both on screen and on the printed page. Outside the Color Picker dialog box, you can work inside any one of these color models by choosing a command from the Image>Mode submenu. In doing so, you generally change the colors in your image by dumping a few hundred, or even thousand, colors with no equivalents in the new color model. The only exception is Lab, which in theory encompasses every unique color your eyes can detect. Rather than discuss the color models in the order in which they occur in the Mode submenu, I cover them in logical order, starting with the most common and widely accepted color model, RGB. Also, note that I don’t discuss the duotone or multichannel modes now. Image>Mode>Duotone repr

Occasionally, the state of computer graphics technology reminds me of television in the early 1950s. Only the upper echelon of Photoshop artists can afford to work exclusively in the wonderful world of color. The rest of us have to be prepared to print many or even most of our images in black and white. Some of you might be thinking, “Wait a second, what about the equalizing force of the Internet? It brings color to all of us!” Well, I concur wholeheartedly. Nearly everyone owns a color monitor, so we can all share color images freely. If this appeals to you. Regardless of who you are print person or Web head color is a prime concern. Even gray values, after all, are colors. Many folks have problems accepting this premise I guess we’re all so used to separating the worlds of grays and other colors in our minds that never the two shall meet. But gray values are only variations on what Noah Webster used to call “The sensation resulting from stimulation of the retina of the

After you bring up an image whether you created it from scratch or opened an existing image stored in one of the five billion formats its size and resolution are established. Neither size nor resolution is set in stone, however. Photoshop provides two methods for changing the number of pixels in an image: resampling and cropping. Resizing Versus Resampling Typically, when folks talk about resizing an image, they mean enlarging or reducing it without changing the number of pixels in the image. By contrast, resampling an image means scaling it so the image contains a larger or smaller number of pixels. With resizing, an inverse relationship exists between size and resolution size increases when resolution decreases, and vice versa. But resampling affects either size or resolution independently. Resizing an Image To resize an image, use one of the techniques I've discussed. To recap briefly, the best method is to choose Image>Image Size, turn off the Resample Image

On top of pixels, alpha channels, color profiles, and all the other image data you can cram into your image files, you can add a variety of reference information where you shot the picture, who owns the image copyright, and so on. In Version 6, this extra data can take the form of cataloging information that you enter in the File Info dialog box or text and audio annotations that you can view and play right from the image window. Recording File Information If you work for a stock agency or distribute your work by some other means, you may be interested in Photoshop’s File>File Info command. Using this command, you can record captions, credits, bylines, photo location and date, copyright, and other information as prescribed by the Newspaper Association of America (NAA) and the International Press Telecommunications Council (IPTC) . We’re talking official worldwide guidelines here. After you choose the File Info command, you see the six-paneled File Info dialog box. Yo

A raw document is a plain binary file stripped of all extraneous information. It contains no compression scheme, specifies no bit depth or image size, and offers no color mode. Each byte of data indicates a brightness value on a single color channel, and that’s it. Photoshop offers this function specifically so you can open images created in undocumented formats , such as those created on mainframe computers. To open an image of unknown origin, choose File>Open As. Then select the desired image from the scrolling list and choose Raw (*.raw) from the Open As pop-up menu. After you press Enter, the dialog box appears, featuring these options: Width, Height: If you know the dimensions of the image in pixels, enter the values in these option boxes. Swap: Click this button to swap the Width value with the Height value. Count: Enter the number of color channels in this option box. If the document is an RGB image, enter 3; if it is a CMYK image, enter 4. Interle

Can you believe it? After plowing through a half-million formats, I still haven’t covered them all. The last three are the odd men out. One format has a purpose so specific that Photoshop can open files saved in the format but it can’t save to the format. The second is a new format that, while moderately promising, is not implemented thoroughly enough inside Photoshop to provide much benefit. And the last is less a format than a manual can opener that may come in handy for jimmying open a file from an unknown source. Photo CD YCC Images Photoshop can open Eastman Kodak’s Photo CD and Pro Photo CD formats directly. A Photo CD contains compressed versions of every image in each of the five scan sizes provided on Photo CDs—from 128 × 192 pixels (72K) to 2,048 × 3,072 pixels (18MB). The Pro Photo CD format can accommodate each of the five sizes included in the regular Photo CD format, plus one additional size—4,096 × 6,144 pixels (72MB)—that’s four times as large as the l

The formats discussed so far are mighty interesting and they all fulfill their own niche purposes. But two formats JPEG and TIFF are the all-stars of digital imagery . You’ll use these formats the most because of their outstanding compression capabilities and almost universal support among graphics applications. JPEG The JPEG format is named after the folks who designed it, the Joint Photographic Experts Group . JPEG is the most efficient and essential compression format currently available and is likely to be the compression standard for years to come. JPEG is a lossy compression scheme, which means it sacrifices image quality to conserve space on disk. You can control how much data is lost during the save operation, however. When you save an image in the JPEG format, you’re greeted with the JPEG Options dialog box (see Figure-1), which grew to include some new options in Version 5.5. But the most vital option is the Quality option, which determines how much compr