What's the difference?

Your computer monitor shows items at a resolution of 72 dots per inch (dpi).  For that reason, the cards shown on this web site are smaller files than the actual scans will be.  Here's some sample math.

A typical postcard is about 3-1/2 by 5-1/2 inches.  Multiply that by 72 dpi, and you have a picture that is 252 dots by 396 dots.
The same card, scanned at 300 dpi, is 1050 dots by 1650 dots.  So, the AREA of the 72 dpi card is 99,792 square dots, if there is such a thing.  The 300 dpi card, however, is 1,732,500 square dots.  The 300 dpi card actually has over 17 times as many total dots.  Whew!  What this means is that it's not very practical to post the cards on a web page at 300 dpi, if your monitor can only show 72 dpi.

There are a couple of reasons for scanning at 300 dpi.  If you want to view the card on your monitor, it means that you can see greater detail on your monitor.  To demonstrate that, click on the sample card below.  The card itself is shown at 72 dpi, but clicking on it opens the 300 dpi card.  Then you can decide if it's worth it to you.

Typical printers use a higher resolution than your monitor.  An inkjet printer usually prints at 200 to 300 dpi (that's why I chose 300 dpi).  Most laser printers will use resolutions of 600 dpi to 1200 dpi, but most people who own laser printers own black-and-white models.  Color laser printers can produce beautiful prints, and I love mine!  It's a Hewlett-Packard Color LaserJet 2600n.  Cost me a measly 300 bucks, and it is ethernet networkable!!  What's the catch?  It holds three color cartridges and one black cartridge.  If I have to replace all four at once, it's about 300 bucks!  (The retail on the printer is $399, but they put it on sale at our local Office Depot occasionally).  This information represents only MY experience with the printer, but I've been extremely happy -- about four months, so far.  Laser printers aren't for everyone, nor are they for every purpose.  Scanning at 600 dpi takes up even more space, so I capped it at 300 dpi.  I figure most people own inkjet printers, so that's our happy medium (and you thought that was a jovial resident of Lily Dale, NY).

Here's the sample card.  I picked one that will show lots of detail, of Celoron Park.  Click on it to see the difference.