On Aug 28, 2004, at 12:08 PM, Doug Franklin wrote:
On Fri, 27 Aug 2004 20:09:45 +0200, Toralf Lund wrote:
[...] to get real picture quality, you ought to have enough information to print at 1200dpi [...]
Most paper can't hold more than 200-300 dpi.
Just to be pedantic...
DPI (dots per inch) applies mainly to halftone processes such as inkjet printers. It refers to the minimum offset distance between two dots. Each of the two dots can be any component colour (usually C, M, Y, K). So the higher the dpi figure, the closer the dots can be printed together, and the "smoother" the image will look from close up.
PPI (pixels per inch) describes the amount of actual information present in the image.
Continuous-tone processes are an exception as the component colours are placed on top of each other, so in this case dpi and ppi can be used interchangeably as the numbers are equal anyway. Scanners and digital minilabs work this way. I think dye-sub printers are like this, too.
Marketing people love to create confusion between these concepts... which is why people tend to refer to dpi all the time as this gives the bigger numbers.
Cheers,
- Dave
http://www.digistar.com/~dmann/
