PICTURE SIZES, RESOLUTION,

DOTS PER INCH (DPI) AND

PIXELS

Definition for: high resolution

The high number of dots per square inch required to produce a high-quality image in printing or on a computer display screen. The higher the resolution, the finer the image quality. Good laser or inkjet printers and scanners provide a resolution of 600 dots per inch and up.

Definition for: low resolution

A low number of dots or lines per inch.
Low-resolution images use less memory but result in a lower print or display quality.
 

Definition for: horizontal resolution

The number of pixels per horizontal line, or the number of columns in a matrix.

Definition for: optical resolution

Most often used when referring to optical scanners or digital camera's, optical resolution is the visible, or physical, resolution at which a given device captures an image. Optical resolution is measured in dots per inch (dpi). Contrast with interpolated resolution.

Definition for: dpi

Dots per inch. A measure of the resolution of printers, scanners and monitors. The more dots per inch, the higher the resolution: 600 dpi would mean 600 x 600 = 360,000 dots per square inch.

Definition for: pixels

A pixel is the smallest logical unit of visual information that can be used to build an image. Pixels are the little squares that can be seen when a graphics image is enlarged. The word pixel is short for picture element. The more pixels in an image, the better its resolution.

PRINTING PICTURES

Print quality images should be created at least 175dpi at the absolute minimum and preferably at 300dpi. 
If you want really clean quality printing that ensures absolutely smooth edges, 600dpi or better if your computer will handle the picture size, will guarantee a great print out.
Remember the more Dots Per Inch (DPI) the larger the file size.

MONITOR RESOLUTION

Your computer monitor can only display between about 72-100 dots of information in every inch of screen (72-100dpi) depending on the screen resolution you have chosen in the control panel.  Once you select it, that is literally the number of dots your screen has in every inch.

WHY SOME PICTURES APPEAR SO LARGE

Good quality print images appear huge on a monitor and pictures that appear good on a monitor typically print off with jagged edges.  For example, an image is defined as 600dpi 6" wide by 3.42" tall.  At 600dpi, 6" = 3600 dots (6x600) and 3.42" = 2050 dots.  The computer monitor only displays 90 dots in every inch but interprets picture information based on total dots and opens the picture as 3600dots X 2050dots not 6" X 3.42" that the picture is defined as. Therefore, on my screen the picture would appear as if it were (3600/90) 40" X 22.77".  This is why the picture appears so huge on the monitor.  To compensate and look at the whole image, set the zoom on the picture to 29% when working on it.  Then the picture editing software only displays about 1out of every 3 dots and you can see the entire image on the screen, although all of the information is still there.

CAMERA RESOLUTION TABLE

HOMEPAGE