Re: [greenstone-users] 2 general questions about imaging standards

From Stephen DeGabrielle
DateFri, 18 Nov 2005 00:30:48 +0930
Subject Re: [greenstone-users] 2 general questions about imaging standards
In-Reply-To (200511161917-jAGJHD6m016867-defang19-it-ohio-state-edu)

These both have information on resolution and compression,


On 11/17/05, mary manning <> wrote:
> First, I hope that it is okay to ask these 2 general questions (not
> specifically related to GSDL). If not, I apologize. But any
> recommendations would be greatly appreciated.
> 1. We are trying to come up with a minimum ppi for our scanning
> standards. This is for our preservation quality Tiffs, not the 72 jpeg we
> will be launching to the internet. We are considering 2 options. The first
> being a min. of 300 ppi for photographs and 400 for handwritten documents.
> (Of course, smaller photographs and slides often need to scanned at a higher
> resolution, and all images need to be scanned to capture the smallest
> significant detail.) The second option we are considering is scanning
> everything at a min. of 600 ppi, as some publishers are requesting this
> resolution (some still only need 300). Is there a trend towards requesting
> 600ppi in the publishing industry? We don't want to have scan materials
> twice (for preservation and labor reasons).
> 2. It is not considered best practice in the archive world to use LZW
> compression for preservation quality Tiffs. (Maybe because it proprietary?)
> Has anyone ever had any problems or heard of any problems with LZW
> compression?

> Thank you so much for your time and for sharing your expertise. Mary
> Mary M. Manning, M.A., Archivist
> Medical Heritage Center
> Prior Health Sciences Library
> The Ohio State University
> 614-292-9966 (ph)
> 614-292-9919 (fax)
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Stephen De Gabrielle