Acquiring Graphics from a Scanner

Many graphics software packages, such as FrontPage, PaintShop Pro, and PhotoShop, come with an interface to a flatbed scanner. This interface lets you isolate an image on paper (or film) and import the image under controls which affect its size, resolution, and color.

When these images are to be displayed on the Web, it is especially important to limit the resolution to the best that most monitors can display: about 75 pixels per inch (unless the image is to be enlarged). Any higher resolution is wasted and can result in much larger files which take much longer to display. Here is an example of using a scanner (the procedures for different scanner packages and from different graphics packages may differ somewhat):

Scanning and Saving an Image Using PhotoShop

• Turn on the scanner
• Lift the lid and place the picture face down, toward the rear of the scanner, and facing toward the rear
• Prepare a directory to recieve the image
• Invoke PhotoShop and click File > Import > TWAIN32
• If you already see an image in the scanner window, it probably is from the last usage, so ignore it. Instead, click on the Preview button near the lower right of the scanner window: you will see the scanner move and display the document currently in the scanner
• If you see a "markee", use the mouse to move it to the desired location in the image, and then shrink or enlarge it to cover just the portion that you wish to scan.
• Set the controls as follows:
  • Flatbed scanner
  • True Color
  • 75 to 150 dpi (depends on whether you enlarge the image or not)
  • No Descreen
  • No Filter
  • 100-200% enlargement
  • [x] Auto Adjustment
• Then click Scan in the lower right portion of the scanner window
• When it finishes scanning, click Exit in the scanner window
• Back in PhotoShop, click Image > Mode > Indexed Color , then select Adaptive and leave the other values default
• Then click File > Export > GIF98a Export . In the window that opens up, if you want transparency, click the eyedropper on that color in the image to be made transparent, and then save the image to the directory of your choice