Date sent:              Sun, 09 Jun 2002 18:59:45 -0400
Send reply to:          [EMAIL PROTECTED]
From:                   "Johnny Johnson" <[EMAIL PROTECTED]>
To:                     [EMAIL PROTECTED]
Subject:                [filmscanners] Re: Archiving and when to sharpen(was:Color 
spaces for differentpurposes)

> At 05:32 PM 6/9/02 -0400,  Mac wrote:
>
> >Wow, are you sure? The LZW TIFF was *larger*?
> >That's unusual.
>
> Hi Mac,
>
> Thanks for asking - it looks like the original TIFF file that I grabbed
> must have already been saved with lwz compression.  So, I did the
> experiment again using a fresh scan of a different slide with the following
> results:
>
> TIFF:                           56,264 kb
> TIFF with lzw compression:      35,364 kb
> JPG with Photoshop level 12:    18,453 kb
>
> So, in both this case and the previous one, the JPG with level 12
> compression is ~ 1/2  the size of a TIFF with lzw compression.
>
> Thanks again for bringing my mistake to my attention,
> Johnny

That makes more sense.
Contrary to what Anthony Atkielski wrote, I have NEVER seen a LZW Tiff come out
larger than an uncompressed one, regardless of exact pixel content.
I have also never seen a compressed TIFF come out equal to or smaller than a JPEG
at the same pixel dimensions, regardless of how how the quality setting of the JPEG.

The only time I've seen a compressed file come out larger than a non-compressed one
is when using .zip on a JPEG.


           Mac McDougald -- DOOGLE DIGITAL
  500 Prestwick Ridge Way # 39 - Knoxville, TN 37919
 [EMAIL PROTECTED]  865-540-1308  http://www.doogle.com

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