Archived posting to the Leica Users Group, 2000/10/03

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Subject: Re: [Leica] JPEG or TIFF
From: John Poirier <mj.patterson@nt.sympatico.ca>
Date: Tue, 03 Oct 2000 10:55:43 -0600
References: <ADF806E8F07ED211A6910000F83086E1ACA920@hrccex.hrcc.on.ca>

Hi-
TIFF is the way to go, as it uses lossless compression.  JPEG uses a
"lossey" compression system.  

When saving a JPEG file, you can choose the level of quality at which it
is saved, which basically amounts to selecting the amount of compression
to be applied. The more compression, the smaller the image file will be.
However, increasing compression also increases the occurrence of
artifacts such as poor colour rendition and pixellation.

A JPEG file saved at high quality can look just fine, but if you keep
the image in that format and repeatedly open and save it there will be
an ongoing loss of quality in terms of the artifacts mentioned above.
The lower the quality setting, the more obvious the degradation will be.

If you are short on hard drive space, high quality JPEGs are not totally
awful as a starter format while you're learning the ropes, but in the
long run TIFF format and storage on CD-ROMs is a better bet.

If you do need major compression for storage purposes, there are
proprietary systems such as Genuine Fractals (which I use) that provide
much better compression and rescaling than JPEG. 

John Poirier

"Lee, Jonathan" wrote:
> 
> Luggers,
> 
> I am just trying out a HP S20 scanner.  The software allows me to save files
> in either TIFF or JPEG format. Is there any advantage in using one or ther
> other, assuming the color and BW images will be exported to Photoshop for
> manipulation and output.
> 
> Jonathan Lee

Replies: Reply from John Coan <jcoan@alumni.duke.edu> (Link to Montana Fire TIFF File (Original) Re: [Leica] JPEG or TIFF)
In reply to: Message from "Lee, Jonathan" <Jonathan.Lee@hrcc.on.ca> ([Leica] JPEG or TIFF)