This is expressed in dots per inch, horizontally and vertically. It's a measure of how many dots it takes to print a solid black 1-inch square. A printer described as 300x300 will use 300 rows, each consisting of 300 dots to print the square. A simple rule of thumb, when comparing printers in the same printer family, is that the more dots are used, the clearer and finer the printed image will be.
