RE: filmscanners: 35mm film versus medium-format scan quality (Ep

[TonySleep@halftone.co.uk (Tony Sleep)]

On Tue, 11 Dec 2001 17:43:25 +0100  Alessandro Pardi 
(alessandro.pardi@inferentiadnm.com) wrote:

> why is that? I mean, that conventional test target images don't work
> properly with digital systems? I was just wondering why nobody had come 
> up
> yet with MTF tests for scanners. Once you can print a MTF target on a 
> piece
> of film (maybe this isn't so easy as I think?) it should be quite easy 
to
> build MTF curves.

Aliasing adds an uncertainty clause to tests done with conventional 
targets. Resolution will vary according to how the target contrast 
boundaries line up with the pixel matrix. Cheap and cheerful workaround 
is to rotate the target so this is minimised, but you can get special 
targets for digital systems, see http://www.sinepatterns.com/ - expensive 
though.

Regards 

Tony Sleep
http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner 
info & comparisons