RE: filmscanners: Scanner resolution (was: BWP seeks scanner)

[Raphael Bustin <rafeb@channel1.com>]

On Mon, 18 Jun 2001, Alessandro Pardi wrote:

> Mmh... I think we're talking about different things: the red channel has
> often the best contrast in *color* images, given the high percentage of blue
> (skies, water) and green (grass) in nature, but that's not inherent to the
> scanning process. If we scan B&W film, we should (theoretically) have the
> same information in all of the three channels. I knew the blue channel was
> prone to noise, but softness in the red is a new (and precious) information
> to me. I will still use it when converting from color to B&W, but not when
> scanning B&W.
> (Or am I totally wrong and you mean the red channel has better contrast even
> when scanning B&W? That doesn't show in the images published in John
> Brownlow's site, though, at least not to a significant extent)


I was thinking color images.  Gotta remember 
that Austin (more often than not) is scanning 
BW negatives.

There is a difference here between the Nikon 
scanners (at least the latest generation) and 
most others -- specifically, the Nikons 
use a 3-line *monochrome* CCD sensor, and 
tri-color (RGB) LEDs -- so they don't suffer 
from the effects of color filters on the 
CCD sensor itself.  Using the Nikon scanner 
driver, you can actually instruct the scanner 
to use just one of the 3 sensor rows, in 
unusual circumstances.  I'm not sure when or 
why one would do that, however.  Something 
about better image quality, for certain 
images with extreme tonal range (???)


rafe b.