Digital BW, The Print

steveabrink wrote:
> 4X5 Black and White Negatives can hold a tremendous amount of 
> information --on the order of 2000+ ppi optical to capture all the 
> potential data.  Yes, it takes tremendous data storage but you can 
> downsample for printing at 360 ppi.    
> SteveB

I've studied this for a number of years now. Listened to lots of 
arguments on the various lists and groups. Asked a bunch of questions 
and gotten all kinds of answers. What it all boils down to is that there 
are three basic schools of thought about scanning resolution. Which you 
believe determines what your favorite scanning resolutions are and what 
your limits are.

The first school thinks that you should scan at max resolution of the 
machine no matter what. Then you down sample to your output size. This 
act of downsizing also downsizes any scanning noise along with it.

The second school thinks that you should scan at "average grain size" 
for the particular film in question. So films like Velvia they scan at 
5000 spi or so, and films like Tri-X at 3600 spi or so. Another part of 
this group thinks it's not so much "average grain size" as it is to scan 
at a solid output resolution (like 300 ppi) at full print size, which 
ends up mostly being in this school for better or worse.

The third school thinks that you should scan considerably under "average 
grain size" to capture just the image information and none of the film 
grain. So they scan around half the resolution of the second school.

Which you believe is sort of like picking a religion. As a drum scanner 
operator I've made the time to do some testing making prints. It doesn't 
matter what the file looks like on your monitor because the object of 
the exercise is making prints, yes? So I made a bunch of scans at 
different resolutions, printed sections of the resulting files and put 
them all up on my proofing wall under the same lights to compare.

My conclusion was that the second school was more fitting for my own 
work -- no lower than 300 ppi output resolution at full print size. 
Clearly YMMV and you should do your own testing to find out what really 
works for you.
--
Bruce Watson