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This chapter is from the book

Setting up and Getting Started

LAB OBJECTIVE

After this Lab, you will be able to:

  • Employ Image Modes
  • Set Up and Get Started

Images in a variety of image modes can be opened or saved in Photoshop. You will probably save your work in progress in native Photoshop file format. You will probably be saving your images for the Web as either GIFs or JPEGs. You should become familiar with all of these, since you may find yourself coverting an image that comes to you in one format into another one that's Web-friendly.

Digital resolution is very different from printed resolution. Print demands much greater resolution for satisfaction than screen delivery ... or perhaps the public is too easily satisfied with low resolution screens. The unit of measurement for each is in dpi or ppi, meaning dots per inch or pixels per inch, yet it is under 100 for Web images at this time (96 for Windows, 72 for Mac), while usually over 1,000 for a continuous tone color photograph in print.

An image can be created from scratch in Photoshop, a digitally created painting or drawing. Yet Photoshop is most celebrated for its manipulation of photographic images. There are several ways of bringing an image into the application: loaded from a digital camera, snapped from a video camera or video segment, or scanned with a flatbed scanner.

Scans are often resampled, where a higher-resolution image is sampled at a lower rate for a screen resolution image that's much smaller and hence loads more quickly on a Web page.

It's a guideline that scans always need tweaking.

When you are finished working in Photoshop, you have several choices for saving your files. Save writes over any previous version of the file you're working on, wherever it resides. Save As initiates the first save and requires you to define a destination for the saved file. Save a Copy saves a duplicate copy to the destination you define, while keeping the previous file on which you'd been working.

Some Notes on Scanning

Think of scanning as a travel ticket. You want the cheapest possible, but don't want to sacrifice comfort beyond a certain level. In your scanned image you want your file as small as possible, yet of acceptable quality.

Whatever make of scanner you have, here is some generic scanning information. The scanner you are using may prove easier or harder to use. Web images and color will be covered in depth in Chapters 8 and 12.

  1. Usually for images that will end up on the Web, you will want to scan at grayscale, Web colors or 256-color (photos), or line art (ink drawings). Scanning at a higher resolution may be useful if you plan to manipulate your images in Photoshop.

  2. Save your images at 96 dpi on Windows PC or 72 dpi on the Macintosh. Your scanner software may have a setting called something like "Web color." You will ultimately be saving your files as GIFs (with .GIF extension on name) or JPEGs (.JPG extension).

  3. An ink drawing, logo, or text should be scanned at setting called "line art" or "document," which produces the highest contrast between black and white. If you scan a photo (black and white or color) at this setting, you'll get an interesting high-contrast effect like a Cuban poster, but you will lose detail.

  4. Give yourself time to experiment with the scanner. Default settings can be pretty good, but figure the first scan is just a test to tell you what you need to tweak—more/less brightness, more/less contrast, and so on. A scan is rarely completely right the first time.

  5. JPEGs and GIFs are usually less than 50K, so if your files are much larger than this, they're probably bigger than necessary.

  6. Make sure you know to where on your hard disk or Zip drive your scanner is saving. It's easy to scan and then have a hard time finding the file.

Save for Web is a very welcome alternative that was added to Photoshop 5.0. This brings up controls that allow you to minimize the size of the image so it will load on your Web page most quickly, yet shows you the image so you can decide if the quality is acceptable.

There is the issue of version compatibility if you are working and saving your file on multiple computers. Remember that an application can usually open a file from a lower version, but not always a higher one. This often greatly affects students who have different versions of an application at home from the one on the school lab machine. If the student does work in the higher version and saves it, it may not open on the other machine.

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