Digital BW, The Print

Austin, Bill,

I don't know whether this is correct or not, so to actually see if there is
a difference I just finished scanning a 6x6 Ilford Delta 100 negative
processed in PMK Pyro @ 364dpi at 24"x24". I am now scanning the same
negative at 4000 dpi at 100%, it should be done in about 30 minutes. I will
post a few extreme closeup enlargements for comparison.

In the meantime,

I looked in the Howtek manual and it states that optical resolution is
controlled by the lens aperture and spatial resolution is controlled by the
dots per inch setting. Increasing the dpi will increase the amount of data
within the image. Optical resolution is expressed as the number of dpi that
can be discriminated, or in simpler terms, how fine in detail each pixel is.
The wider the aperture the softer the image is.

Howtek told me that by scanning at a listed optical resolution, the scanner
will automatically adjust the lens aperture to accommodate the final image
size. It will not interpolate up the file. Maybe they were pulling my leg?

Mike.



----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Thursday, March 21, 2002 9:50 PM
Subject: RE: [Digital BW] Re: scan vs. printer resolution (WAS: combingcure)


> > Mike, I'm not sure I'm following you.  Are you scanning the negative
@364
> > DPI or is the 20x20 print @ 364 DPI?
>
> Bill,
>
> He's talking about a different beast then you are probably used to.  I'm
not
> saying he's right or wrong, as I don't know his scanner, but PMT scanners
> (Photo Multiplier Tube), AKA drum scanners, aren't subject to the
resolution
> issues CCD scanners are.  They only use a single element sensor, and an
> aperture.  The aperture is typically selected such that the width of the
> resolution is covered.  It's the drum that moves in an XY pattern,
> illuminated from within for film, to scan the media.
>
> Regards,
>
> Austin
>
>
>
> Please visit the Group Homepage to check the Files, Bookmarks, Polls and
other resources as they are often being updated. The page is at:
>
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
>
> Please follow these basic guidelines:
> - Include your full name with your message.
> - Include the address of your website, if you have one.
> - As threads develop, trim off excess portions of earlier messages to keep
them short.
> - As the topic of a thread changes remember to change the subject header.
> - Good manners are required at all time. No personal attacks or "flames."
> - Complete your Yahoo profile.
> - Before posting a question, search the message archives and the various
resources on the homepage.
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>