[filmscanners] RE: File size in PS?

["Paul D. DeRocco" <pderocco@ix.netcom.com>]

Didn't Windows Explorer tell you the answer to your question? PS uses simple
LZ encoding, while Vuescan appears to use LZ on the difference between
successive horizontal lines, which provides better compression. Why PS
doesn't have it is beyond me.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com

> From: Nagaraj, Ramesh
>
> At maximum resolution, single pass, my Minolta Elite II generates
> 35.MB TIFF file.
> If I open the above file in PS and do a "SaveAs"(with LZW
> compression), file size increases. I do not know why?
>
> Here are details.
>
> Vuescan file size- 35MB
> PS "SaveAs" with LZW - 56MB
> PS "SaveAs" without LZW - 66MB
>
> I looked at the Explorer/Properties/Summary for both Vuescan file
> & PS file. The changes are as follows.
>
> ****** Vuescan file summary (Looked using
> Explorer/Properties/Summary) *****
> Compression-
> Lempel-Ziv with Tiff Horizontal differ...
> File size- 34.7mb
>
> *** PS "SaveAs" file summary (Looked using
> Explorer/Properties/Summary) ****
> Compression- Lempel-Ziv
> File Size- 66MB
>
>
> So the difference between the two is; PS uses Lempel-Ziv
> "Lempel-Ziv Horizontal differ..." compression while Vuescan
> follows "Lempel-Ziv" compression.
>
> I tried using VuePrint for compression, it reduced the 34MB file
> to around 20MB.
>
> My questions are
> a) Why the "SaveAs" in PS increses the file size?
> b) "VuePrint" for file compressses more than PS & "VueScan";
> Does it mean "VuePrint" use latest LZW technology which PS6.0
> does not implernent?

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