Film Scanner Resolution

Archived from groups: rec.photo.digital (More info?)

I enquired at a film processing shop as to transfer my old transparencies
and negatives to CD and asked as top what resolution they would be scanned
at. I was told it be 30,000 dpi standard rate or even a higher dpi is
achievable at a premium. Whilst the numbers sounded good initially, I then
looked at a number of 35mm film scanners and note that they go nowhere near
the figure I was quoted. My qustion being, are there pro scanners which can
scan at these resolutions or was I mis quoted?

Archived from groups: rec.photo.digital (More info?)

Chef! wrote:

> I enquired at a film processing shop as to transfer my old transparencies
> and negatives to CD and asked as top what resolution they would be scanned
> at. I was told it be 30,000 dpi standard rate or even a higher dpi is
> achievable at a premium. Whilst the numbers sounded good initially, I then
> looked at a number of 35mm film scanners and note that they go nowhere near
> the figure I was quoted. My qustion being, are there pro scanners which can
> scan at these resolutions or was I mis quoted?
>
>

Some of the top drum scanners go to 11,000 dpi.
30,000 dpi = 0.85 micron. While micron class resolution
is theoretically possible, it would be really difficult
to achieve because the multiple layers in color film
would be tough to keep in focus. The highest resolution
color films, like Fujichrome Velvia do not need to be
scanned at such high resolution. Most detail is recorded
with approximately 4,000 ppi, and essentially all by 6000
to 8000 dpi. The main advantage of higher resolution
is better definition of grain, reducing grain aliasing
(which in my opinion, grain aliasing can degrade the image).
This page shows some scans up to 8000 dpi:

http://www.clarkvision.com/imagedetail/scandetail.html

This page describes many scanners:
http://www.terrapinphoto.com/jmdavis

A google search will turn up many others.
Roger