Scanning Images

  Color scanners are available to the Rensselaer community in the Macintosh Lab in Sage 4711 and at the VCC Help Desk (attached to a Mac), and in the southwest lobby of the VCC attached to a PC.  You can reserve time on the scanner at the Help Desk.

Each scanner is set up slightly differently. If you're not familiar with using a scanner, look at Memo RPI.126, Scanning Images and Text, or ask a consultant to help you.

Here are some tips that you might find useful:

• Use a low resolution when scanning images for on-line viewing. Screen resolution is generally not that good, so scanning an image at 300 dpi (dots per inch) is really a waste of disk space. Try scanning at 75-100 dpi for images you plan to use on-line.
• Scan small pictures, or small parts of larger pictures. Many viewers might find that large images slow down their browser intolerably. For best use on-line, use small images and keep overall file sizes fairly small. A 1MB file, which is easy to get when scanning a color photo, is way too big for most people's taste (and patience) when it downloads to the Web.
• Try reducing the number of colors in an image. Even a black & white photo can have 250 kinds of gray in it. On RCS, you can enter a simple one-line UNIX command to reduce colors:    

  giftoppm banner.gif | ppmquant 32 | ppmtogif > banner.gif
  

  This will take a GIF file and reduce it to 32 colors. You can try other numbers as well, such as 16.
• Preview your image and make sure it is bright enough and looks the way you planned. The best way to do this on RCS is to use the xv utility. Open a file in xv using the UNIX command xv file.gif. Right-click on the image to bring up a separate control window; from this window, left-click on the Windows button. A pop-up menu should appear; select the Color Editor menu option to start up the color editing panel. The easiest way to further adjust the color is to click on the Brite or Dim options. There is also a cropping function and a menu of Image Size options that let you reduce or increase image size by 10%, or halve or double the image size. The xv package also allows you to save your image to different formats.
• To convert an image from a TIFF to a GIF format on RCS, use the command tifftopnm file.tif > file.pnm. You can then look at the PNM file with xv, make your adjustments, and save the file as a GIF.

      There are probably hundreds of ways to convert images and improve them, so you might want to experiment and try other methods.