Lithography definition

Lithography is a four-color separation high volume printing process with ink.  It is the most efficient form of photomechanical reproduction.  An art piece is first scanned and then divided in the CMYK color channels on four printing plates.  The printing plates are printed one after the other in order to make a full color image.  At this point individual colors are added on more plates to order to make special effects like a varnished area or gold ink.  These special effects cannot be created from CMYK in the normal Pantone range.  They are known as spot colors.  Nowadays artists may continue to use stone lithography to make their artwork.  However, by hand the process takes much longer.  The main technique for either method involves grease that rejects water.  The grease areas will stay white and the rest of the areas will take on ink (and hence will print).