Adobe Photoshop CS2 and Adobe ImageReady CS2

Adobe Photoshop CS2 and Adobe ImageReady CS2 would have been Photoshop version 9 and ImageReady version 9, respectively, if Adobe had not renamed them for the Creative Suite.

Where Photoshop and ImageReady Came From

What started out as a personal project for Thomas Knoll and his brother John in the late 1980s turned into Adobe Photoshop, an image-editing program that has since redefined how we look at computer graphics. Photoshop has since become a verb ("I just Photoshopped his head in the picture"). And Adobe has created other products, such as Photoshop Elements (a consumer version of Photoshop) and Photoshop Album (a digital photo album), an endeavor that almost makes the name Photoshop into a franchise itself.

What Photoshop Does

Adobe Photoshop is what's generally called a pixel-based (or raster-based) paint program. A raster is a matrix of dots, called pixels, that form to make a picture or an image (see Figure 2.1). The number of pixels in a raster image defines the resolution of that image. The resolution is usually specified as dpi (dots per inch) or ppi (pixels per inch); you've probably heard of images being described as 300dpi, for example. This means that for every inch in the raster image, there are 300 pixels or dots. Think of it as a level of detail: To fit 300 pixels in 1 inch, you have to make them a lot smaller than the size of pixels you would need to fit 72 pixels in an inch. Having more and smaller pixels gives you better detail (see Figure 2.2). That's why when you hear people talk about professional-quality images, they refer to them as high-resolution images.

Figure 2.1. A low-resolution raster, each square representing 1 pixel.

Figure 2.2. The more pixels, the better the detail.

I know what you're thinking: If higher-resolution images look better, let's crank up the resolution to something like 1000dpi everywhere. Well, it's a bit more complicated than that. First, the resolution of an image is determined when the image is created. When you scan an image using an image scanner, it gets scanned at a resolution that you set; when you take a photo with a digital camera, the photo is taken at a specific resolution; and when you create a new Photoshop document, you're asked to determine what resolution you want the document to be (see Figure 2.3). After a resolution is set for an image, it can't be changed. This means that if you enlarge a 300dpi photo to be twice its size (200%), the resulting image will be 150dpi. The pixels themselves get enlarged when you scale the photo, resulting in bigger pixels. What you get is usually less than ideal, resulting in a blocklike, jagged-edge image. When an image is such that you can see the individual pixels, it is called pixelated (see Figure 2.4).

Figure 2.3. Setting the document resolution in Photoshop's New dialog box.

Figure 2.4. A pixelated image.

By the Way

Okay, so I lied. You can change the resolution of an image using a process called resampling. Luckily, you have the best tool to resample with: Photoshop. Downsampling an image means you're reducing the number of pixels, such as reducing a 300dpi image to 72dpi for use on the Web. Basically, extra pixels are thrown out of the image to bring the resolution down. Upsampling occurs when you increase the number of pixels in an image. Photoshop uses a process called interpolation to create the necessary extra pixelsbut increasing the number of pixels won't increase the level of detail or make for a better image.

Photoshop might rely on resolution, but its power lies in how it can manipulate those individual pixels. A wide range of pixel-based tools and effects gives you complete control over any image. By control, I mean the capability to change each and every pixel in your image. The following is just a sample of the kinds of tools and effects Photoshop provides:

• Color correction and tonal filters to adjust the overall look of an image or to add special color effects, such as sepia tones

• Cloning tools to manipulate or retouch images, such as adding or removing items from a photo

• Blur and smudge effects to smooth out parts of an image or to add a sense of motion

• Layers and alpha channels to assist in compositing multiple images into a single image, as in a photomontage or collage

• A Magic Wand tool and other selection tools to choose which parts of an image you want to adjust or work with

I'd like to focus on that last item for a moment. The one thing you'll do most often within the Adobe Creative Suite is select things. Until the day comes when computers can read our minds (and I constantly live in fear, knowing that day will come), we have to tell Photoshopor any program, for that matterwhat we want to do. More specifically, we need to indicate what part of the image (or the page, the illustration, and so on) we want to work with. As you'll come to see, your options for the kinds of functions you can apply depend on your selection. It's hard to change the font for some text if you have a blue circle selected. We discuss how to make selections as we cover each of the programs in Part II, "The Applications."

What ImageReady Does

Something we haven't touched on yet is web design. Although Photoshop has the tools to create web graphics, it does one better by including an entire program suited for just that purpose. Adobe ImageReady was once a standalone product but has shipped as part of Adobe Photoshop since version 5.5. ImageReady does one thing only: create web graphics. A handy Edit In button (see Figure 2.5) lets you easily move images from Photoshop to ImageReady (and vice versa).

Figure 2.5. The Edit In button in Photoshop that opens your file in ImageReady.

Following is a list of some of the kinds of tools and functions you'll find in ImageReady:

• Optimization settings and web previews to easily specify image formats such as GIF, JPEG, and SWF

• Slice tools to cut up images into HTML tables for better and more flexible design options

• An intuitive Rollover palette that enables you to specify interactive rollovers

• An animation palette to help create graphics that move on the Web

• Many Photoshop-like tools and effects to make adjustments to your web graphics

By the Way

If any of the terms listed hereHTML, GIF, and so fortharen't familiar to you, don't worry; we cover each of these in detail in Chapter 6, "Using Adobe ImageReady CS2."

Now that you have a better understanding of what Photoshop and ImageReady can do, let's discuss when you should use these tools.

When to Use Photoshop and ImageReady

Photoshop and ImageReady are perfect for various tasks, including the following:

• If a photograph is too yellow, too dark, or too blurry, or just needs adjustments in the highlights or shadows, you can access all kinds of tools and functions to make it just the way you want itsuch as the cool Shadow/Highlight feature, for example. Likewise, blemished photos (ones with fingerprints, scratches, or cracks) or old, damaged photographs can be repaired with cloning tools or Photoshop's spectacular Healing Brush tool.

• Photo compilations such as collages and montages are perfect for Photoshop. With layers, masks, alpha channels, and more, Photoshop is well equipped to combine multiple images into single compositions.

• Photoshop excels at web design. A large majority of the websites you see every day are designed using Photoshop. Because Photoshop allows for such precise control over the individual pixels of an image, designers can tweak pixel-based web graphics to perfection.

• Web design is only half the job. Preparing graphics for the Web, such as optimizing, slicing, and adjusting the number of colors (otherwise called Web production) is just as important. Photoshop combined with ImageReady is perfect for this kind of work.

• Do you consider yourself an artist? Photoshop is often used for digital painting and fine art. Attach a pressure-sensitive graphics tablet (such as a Wacom tablet) to your computer, and you can take advantage of Photoshop's powerful brush engine to create paintings and original art.

• Final art preparation and production is a necessary task in just about every project. Whether it's resizing a photo, converting an image from RGB to CMYK or from a JPEG to a TIFF, or specifying spot colors for a duotone, Photoshop is up to the task. A perfect utility tool, Photoshop can both open and export a wide range of file formats.

• Sometimes photos or images need that special touch, such as vignettes or soft drop shadows. Photoshop's powerful selection tools and feather commands make it the perfect tool to add these popular effects.

• Photoshop is a great tool for capturing digital images from peripheral hardware such as a scanner or a digital camera. Photoshop's File Browser makes it easy to find the images you need, and the File Info dialog box enables you to add metadata to a file.

As you can see, Photoshop can be used to perform a wide range of tasks, but keep in mind that there are certain things you don't want to use Photoshop for. Because it's pixel-based, you want to avoid using Photoshop for art that will be scaled to different sizes (logos, for instance). Things that might require a lot of editing or changes, such as text headlines, should also be avoided because it's time-consuming to make those changes in Photoshop.