Look for optical resolution in the specs.
Ars Brevis Press
> From: "c. cano" <fuzzy44@...>
> Reply-To: PPLetterpress@yahoogroups.com
> Date: Thu, 15 Aug 2002 13:22:19 -0700
> To: PPLetterpress@yahoogroups.com
> Subject: [PPLetterpress] Re: Maximum resolution
> Good thread!
> After reading these posts about resolution, I thought this would be a good
> time to
> I am in the market for a new scanner.
> My current scanner, an Epson ES-800C (practically an antique by today's
> needs to retire.
> I need something for hi-res color, grayscale, line art and also for
> I have firewire and SCSI ports - and could add USB.
> Any recommendations?
> (Drum scanner not an option)
> Katie mentioned that some scanners use "interpolated" resolution.
> How do you know if a particular scanner scans this way?
>> I don't understand why this should be so. I've worked with line art
>> tiff files in Photoshop at 16 x 24 inches and 1200 dpi and have never
>> encountered the limitations you are describing. I do a lot of image
>> reconstruction for institutions and fine presses etc...
>> If it helps: My usual procedure is to scan line art in grayscale at
>> 600 dpi. This scan is brought into Photoshop and I double the
>> resolution to 1200dpi (you can do this once, and only once). Though
>> grayscale does quadruple the memory requirement, the active memory
>> that is required to manipulate a grayscale file is much less than
>> that required for a b/w bitmap image. Only after I have cleaned up
>> the scan to my satisfaction will I change it to a b/w bitmap and save
>> as a tiff.
>> It is often easier to work with a file in Photoshop if you save your
>> scan as a Photoshop doc rather than as a tiff. Only the finished document
>> needs to be saved as a tiff.
>> Though the final imagesetter needs to read your Pagemaker or Quark
>> document at 2560 or higher, and you DO need to set this as your
>> printing resolution in the page layout program, any line art that is
>> imported into that document only needs to be at 1200dpi (camera ready
>> quality) to avoid the bitmap jaggies.
>> Back to your initial concern. Is this perhaps a memory limitation?
>> Have you considered boosting the memory of your scanning/image-
>> editing/page layout programs as well as expanding and cleaning out
>> the scratch disk for Photoshop? And, most importantly, do you have
>> enough active RAM to handle this work? Also try working with these
>> programs in stages (one at a time rather than having them all open at
>> once), rebooting after each program is finished.
>> Message: 5
>> Date: Mon, 12 Aug 2002 18:08:18 -0400
>> From: Katie Harper <knharper@...>
>> Subject: Re: Re: Maximum 30,000 pixels?
>> Gerald makes some good recommendations for working with large files. After
>> reading this exchange, however, I'm wondering if the point is not being
>> missed somewhere along the line. There are all kinds of rules of thumb for
>> scanning resolution and output resolution. What is not touched on is a) the
>> quality of the original; the quality of the scanner (many scanners will give
>> you "interpolated" resolution that sounds very high but in fact is not); and
>> finally, and most important, the quality of the final printed piece. If you
>> are going to make a plate for printing line art with letterpress, you have
>> to consider what paper you are printing on (coated v. uncoated, for
>> example); the state of the press, rollers, etc. In any printing process, all
>> such factors must be considered; because of them, and many others not
>> mentioned here, there is a point beyond which the naked eye will not be able
>> to notice the difference between 1200dpi and 2450dpi, for example, and any
>> effort to get "higher" quality will be a waste of time. My recommendation is
>> to do some tests with various resolutions (you might want to test a smaller
>> file) and print the results on your printing press or laser printer or
>> whatever output device you are planning on using, and see where the drop off
>> in quality happens. You might be surprised.
>> Katie Harper
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