Re: filmscanners: Pixels per inch vs DPI

[Wire Moore <wirem@home.com>]

on 10/22/01 11:54 PM, Rob Geraghty at harper@wordweb.com wrote:

> Austin wrote:
>> Why would you want to output at a fixed 300 PPI?
> 
> Because that's the requirement of the offset printer which many of my recent
> photos are going to.  Aside from that, 300 dpi is as a general rule of thumb
> the "best" resolution *most* printers (pc and otherwise) work with.  Some

[snip]

After working with 4-color Epsons for a few years, I've found that the
resolution demands of photographs can be quite low, where as few as 100 ppi
as a lower limit can produce nice results. Vector images are more sensitive.
Type often requires 300 ppi.

There's a book called "Real World Scanning & Halftones," which explains
print dots (spots) in depth. It's focused on printing presses using halftone
and line screens, but also covers stochastic screening (as used in inkjet
printers), and provides explanations of the relationship of spot
construction and screen frequencies to image fidelity.

Not essential reading, but interesting.

Wire