Message-Id: <199801220558.WAA57382@dns.ccit.arizona.edu> Date: Wed, 21 Jan 1998 23:12:41 -0700 From: Robert Hershoff <mailto:hershoff@BIRD.LIBRARY.ARIZONA.EDU> Subject: Re: group 4 compression To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
January 21, 1998Remember that the jpeg images use lossy compression - any manipulation, including format changes to .tif, is liable to adversely effect image quality.
If you have access to the original images, you'll have better quality if you rescan than if you convert jpeg to .tif.
Robert
***************************************************** Robert Hershoff / The University of Arizona Library Main Library Room A304 / 1510 E. University Boulevard P.O. Box 210055 / Tucson, AZ 85721-0055 voice (520) 626-7415 / fax (520) 621-9733 e-mail: mailto:hershoff@bird.library.arizona.edu *****************************************************
On Wed, 21 Jan 1998, Garry Forger wrote:
> To follow up on my earlier question about group 4 compression. I have
> found that if I bring the image into Photoshop 4.01 (they are .jpg or .gif
> images) and save them as .tif I can import them.
>
> Apparently the default for saving in Photoshop is group 4 compression (?).
> The only option in Photoshop is to save as LZW compression, and if I do
> that I cannot import the images, I get a message saying it must be group
> 4.
>
> The documentation for photoshop does not mention this group 4 as a
> default, but I did get it to work.
>
> Thanks everyone for the suggestions, I did look at some of the software
> that was suggested and they were helpful in defining the problem.
>
> Garry
>
> =========================================
> Garry Forger, MLS
> Assistant Librarian
> University of Arizona at Tucson
> mailto:gforger@bird.library.arizona.edu
> 520-621-8753
> =========================================
>
> On Wed, 21 Jan 1998, Emil Levine wrote:
>
> > Paperport for HP will output TIFF Group IV CCITT compressed. Otherwise
> > you have the LZW which I think is referred to as TIFF 3 or 5.
> >
> > >----------
> > >From: Garry Forger[SMTP:mailto:gforger@BIRD.LIBRARY.ARIZONA.EDU]
> > >Sent: Tuesday, 20 January 1998 19:58
> > >To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
> > >Subject: group 4 compression
> > >
> > >I am trying to find a utility that will save images as 'group 4
> > >compression tiffs'. Photoshop only saves tifs as LZW compression. If
> > >anyone has a simple piece of software, (or shareware) that can help me
> > >with this please let me know.
> > >
> > >There are a group of images that have already been scanned and saved as
> > >either .jpg or .gif files that I am trying to convert.
> > >
> > >Thanks,
> > >Garry Forger
> > >
> > >=========================================
> > >Garry Forger, MLS
> > >Assistant Librarian
> > >University of Arizona at Tucson
> > >mailto:gforger@bird.library.arizona.edu
> > >520-621-8753
> > >=========================================
> > >
> >
>