Scanned Photograph or Digital Printing Requirements

Below you will find a few tables outlining print resolutions and there absolute digital equivalents.  First I want to note that I have built these tables around a 300dpi US pre-press standard.  Many people print photos at 250 dpi too, therefore those folks would need slightly less resolution.  Also please understand that the tables are absolute values, all print drivers and photo finishers will interpolate the needed mega-pixels to produce enlargements from a lower resolution image.  That is not to say that at some point you will start to see grain and loss of sharpness from those lower resolution images as the are enlarged beyond a certain point. 

If you want to print an enlargement from a lower resolution image (as we all do) I recommend using Photoshop (or equivalent) to resize the images before you either print it or have a photofinisher print it.  Please remember that pixels and dpi are not the same, once you resize your image also set the printing dpi in your image manipulation software too.