The smallest item that can be printed by a digital output device is called a "spot". A spot is never one fixed size. The size of the spot is determined by the resolution of the input or output device. A typical computer monitor has 72 spots per linear inch while a film imagesetter may have more than 4000. A typical digital press prints at 600 spots per inch with a few models printing 800 or more per linear inch.

The "spot" is often confused with the "dot" as in "dots per inch", but a printed dot is actually made up of a group of spots. It is common to refer to the resolution of an output device as dots per inch (dpi), even though it actually means spots per inch. In digital terms, a dot (group of spots) is made up of a grid of bits. A bit is the smallest unit of digital information and is represented by either a zero or a one (either on or off). A grid of bits is called a bitmap. Groups of dots are used to create halftone images, which are used to represent continuous tone images, such as photographs, in a printed form.

A bitmap can be expanded to a depth of eight layers. Eight bits equals one byte, so the multi-layered bitmap is called a bytemap. Eight bits of information allows for the creation of a multi-layered dot called a pixel, which contains 256 levels of gray, and when combined with other pixels, creates millions of colors. The available color depth is also known as bit depth.

The typical resolution of a digital press is lower than a traditional imagesetter or platesetter used for offset printing. With an average print resolution of 600 dpi, the presses must use some type of screening enhancement software to simulate the typical line screen of 150 lines per inch achieved by offset equipment.

Digital presses with a resolution of 600 dpi or better do a good job in reproducing images that are clear and sharp. Applications printed on digital presses with lower resolutions (400 dpi) will not reproduce images with the same level of quality. Printed text may look a bit fuzzy and it may be possible to see the actual printed dots that make up the text.

It is advisable to scan images as close to the finished size as possible. Images should be scanned in CMYK rather than in RGB mode. RGB is meant for images that will remain in an electronic form, such as for viewing over the Internet.

Because digital presses print at at fairly low resolution, they do not use a fixed line screen, but instead they simulate the average screen ruling used for offset printing which is usually around 150 lines per inch. Images below 250 ppi should not be used for digital printing applications. Since a resolution of 300 pixels per inch is standard for applications printed with offset technology, the same resolution should be used with digital printing. If the application is printed conventionally on some occasions and digitally on others, it is helpful to use the same resolution for both.