Re: Digicam vs. Scanner resolutions

[Kennedy McEwen <rkm@xxxxxxxxxxxxxxxxxxxx>]

In article <3D057114.FCDF73FD@worldnet.att.net>, Phil.Lippincott 
<phil.lippincott@worldnet.att.net> writes
>Kennedy,
>      I'm sorry this isn't an academic discussion.  Aztek has clients 
>doing bill
>boards from crops within 35mm.  No there is no visible grain on the print I
>referred to.

You still don't get it do you?  Resolution, and neither GRAIN nor SCAN 
QUALITY, is the issue with your claim!  I don't think I have even 
mentioned grain other than to address the issues on that topic raised by 
other contributors to the thread.

 From the start my concern has been resolution, as determined by the film 
and optic MTFs - and assumed that the scanner MTF is controlled to match 
the sampling density and therefore less of an issue.  As mentioned 
several times already by myself and others, resolution is not determined 
solely by film grain and, indeed, granularity is only a very rough guide 
to the resolving capability of a particular film.  Someone else even 
posted figures for granularity and resolution of Provia and Velvia which 
support that view.

There simply is not enough IMAGE resolution recorded on film for a 150in 
print from a 35mm frame to appear sharp at close inspection, as you 
claimed - that is not academic, it is just a fact of life.  I am sure 
that Kodak would love to hear that you have recovered far more 
resolution from Ektachrome than it is possible of supporting - and they 
would jump at the chance of providing evidence which would knock Fuji 
from the resolution pinnacle.

Similarly, scanning at 8000ppi and reproducing at 150in results in a 
pixel resolution on paper of only 80ppi - and anyone can examine what 
that looks like under close inspection on a small to medium scale.  Even 
taking measures to reduce pixelation visibility the result is much 
softer than what is typically regarded as pin sharp.

You made the claim of a perfect image at that size right up to the 
closest viewing conditions and that is what I have taken issue with 
because, whilst impressive, the limited resolution means it is far from 
perfect.  A comparison with an image from a large format, or even a 
lower magnification from a 35mm frame will make the poorer resolution 
obvious by yielding a much sharper result.

> Drum scanners do not use an optics lens to see or reproduce images.

I am fairly familiar with how drum scanners operate and how grain is 
controlled by their relative merits compared to CCD scanners, and have 
seen many examples of scans from them, as well as discussing how some of 
the grain control features of drum scanners can be approximated by CCD 
systems on this list.  None of that changes the situation regarding 
image resolution.  There simply isn't any resolution on the film image 
to recover, whether grain is present or not.
-- 
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers
-
Turn off HTML mail features. Keep quoted material short. Use accurate
subject lines. http://www.leben.com/lists for list instructions.