                              DPI_NOTE.TXT

Offered for you here, are the ins and outs of "dpi" and issues
of file verses printer resolution.

"dpi" means dots per inch.

The BMP file format has locations to store both the vertical and horizontal
resolutions of the image it contains. Some graphics editors make use of 
this and some do not. 

Usually, if you use a digital image scanner, it will store its own 
scanning resolution in the resultant file. When you print this file,
without changing anything, it should come out exactly the same size 
as the original document you scanned. So, if you scan a photo at 400 dpi 
and print it on a 360 dpi printer, you will actually lose some of the image.
Anytime that you print a picture that has a file dpi greater
than your printer dpi, your printer will have to omit pixels
to accommodate.

Some graphics software let you change the dpi of the file, before
you print it. A good way to get a handle on things is to change all 
your pictures to the dpi of your printer. That makes it easy to figure
how your enlargements will work out. If you print at 200% then each
pixel of your file will be printed as 4 dots on the page (2 x 2).
Integer multiples produce the smoothest enlargements; 200, 300, 400%, etc..
Because, each pixel will be printed as a perfect square of dots and all
will be exactly the same size. The importance of using integer multiple
enlargements diminishes as the size factor increases. Any enlargement 
factor over about 500% looks pretty uniform.

The images produced by the example programs included with this zip file
are all going to be 360 dpi. That's what my printer is. If you register this
package, I can make adjustments for whatever printer you are using.

A special note about Windows Paintbrush:
If you open a bitmap file in Paintbrush and save it from there,
Paintbrush will change the file dpi to 25. I can only assume that
since there is no apparent use for file dpi built into this application,
these are simply erroneous numbers.
