What is scanning and dpi?
Scanning is the process of converting paper or images to a digital format and in this process the number of “dots-per-inch” or dpi is used to adjust the amount of detail of the scan. The dpi setting of the scanner relates to the final pixel size of the scanned image. If you put a 4″ x 6″ photo on the scanner and scan it at 300 dpi, the resulting digital image will be 1200 x 1800 pixels in size (4″ x 300 = 1200 and 6″ x 300 = 1800). The higher the scanner dpi setting the more information is being collected resulting in better image clarity. With slides that are approximately 1″ x 1 1/2” the dpi setting for the resulting image should be based on the desired output format (printed picture or digital viewing – TV, computer monitor, etc.). For example, to obtain a clear 4″ x 6″ printed photo you would have to scan the slide at a minimum of 1200 dpi to get the same results as scanning a 4″ x 6″ photo at 300 dpi. Best results for paper photos are generally achieved within a range of 300 dpi
