Image and resolution/Scanners

Image and Resolution

The most important thing to remember when working with digital images is to know how the file will be used. It’s good practice to use compression, to reduce the size and pixels per inch (ppi), to ensure that the image meets your needs.

If the image is to be used on a web site, the image should be reduced to 72 or 96 ppi, as most monitors don’t support much higher than this. Another reason you don’t want to have too large of an image, is that it might take someone too long to download the image from a web page. Now if you plan on printing an image, it’s better to use a higher resolution. It’s good rule of thumb to use between 200-300 ppi. However, be careful when trying to email an image to someone else for them to print, because the image may be too large and might get blocked by email filters.

Scanners

There are quite a few different types of scanners, but the most common is the flatbed scanner. The function of a scanner is to convert a picture or document to a digital format that can be used by a computer to either display or manipulate. It's a great tool to use for posting documents to a web site or to convert documents to send via email. The hardwired interface between the scanner and the computer can be either usb, parallel, SCSI, or FireWire, and it uses a “protocol” called TWAIN to communicate between the two.

Important things to know about scanning: what size picture/document will be scanned and how big with the image be when it’s displayed. This will help determine what dpi to use when using a scanner.