Resolution is measured in samples per inch or SPI. People often, to include us, refer to resolution with the term DPI or dots per inch. SPI and DPI describe the same thing. DPI means that a scanner will capture so many dots or pixels for every inch of area scanned. For example, if you were to scan a 5”x7” photograph at 600 DPI you would end up with a digital image that is 3000 pixels wide and 4200 pixels in height. Simply multiply the resolution, 600, in this case, by the dimensions of the photo being scanned, 5 x 600 = 3000 and 7 x 600 = 4200. The higher the resolution, the more pixels the resulting digital image will contain. The more pixels an image contains, the more detailed the digital image.