Resolution is not the only thing. Check out the link I posted
previously. The Imacon scan was done at 3600ppi and the drum scan at
2400ppi. The drum scan was indubitably better even on the monitor at
reduced size.
http://www.xs4all.nl/~diax/pages/mamiya_boot_scan_compare.html#
so folks won't have to look up the post.
graywolf
http://www.graywolfphoto.com
"Idiot Proof" <==> "Expert Proof"
-----------------------------------
Godfrey DiGiorgi wrote:
On Sep 26, 2005, at 6:21 AM, mike wilson wrote:
Theoretically yes, practically no. Unless like others have said you
can afford
to buy a 12000 dpi drum scanner or alternately afford to pay ~US $50
per scan
for the privilege. And then it wouldn't be usable unless all
colour/level/gamma
adjustment could be perfected at the point of capture.
This is what I find paradoxical about the whole "digital
revolution". On one hand, there are statements like the above -
12,000dpi to extract anything like the full information from a 35mm
frame. On the other, there are the "6mp is enough" brigade. I know
they are not exclusive.
As I said, the advantage of scanning devices like the Imacon is
primarily tonal rendering, not significant image data. Of course,
quantizing a unit area of film to a higher degree and providing more
pixels will allow printing to even larger sizes. Digital printing is
different compared to optical printing in that quality improves as
you make the print larger right up to the point where pixelation
becomes visible. So with a 12,000 ppi scan, you're going to be able
to make a 60x40 inch enlargement at 300 ppi output size. But you're
NOT going to see significantly more quality in an 11x17 inch print.
How many 60x40 inch prints do you plan on making? ;-)
To make an 13x19", 300ppi print from 35mm requires scanning at 4000
ppi. Unless you need a larger print, or need to crop a LOT, you don't
need more.
That I understand. Is the ISO scale linear wrt grain size? If so,
I assume that to get the same effect from a 25ISO frame you will
need to scan at 128,000dpi.
Grain size is non-linear and complex to calculate as it changes with
processing methodology, sensitivity, gamma, and acutance.
Godfrey
