Question:Do you lose quality if you RAR/ZIP your pix?

Started Nov 8, 2001 | Discussions
David (r00t)
David (r00t) Veteran Member • Posts: 3,308
Question:Do you lose quality if you RAR/ZIP your pix?

Does the compression affect the quality? I use WINRAR for compression. If affected, do other compression programs alter pictures differently? Is one proggie better than the other when it comes to pictures?

TIA

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alex wetmore Senior Member • Posts: 1,394
Re: Question:Do you lose quality if you RAR/ZIP your pix?

r00t wrote:

Does the compression affect the quality? I use WINRAR for
compression. If affected, do other compression programs alter
pictures differently? Is one proggie better than the other when it
comes to pictures?

No. RAR and Zip are lossless compression techniques.

They are also unlikely to compress the pictures very much. The zip algorithm saved me all of 1k on a full resolution, fine quality picture from the DSC-F707. JPEG is already a compressed format.

alex

.Ray Contributing Member • Posts: 602
Re: Question:Do you lose quality if you RAR/ZIP your pix?

Also, if you try to zip up a already highly compressed jpeg file, you can end up with a bigger sized file than the original.

eg a friend sent me 5 jpg files in a stuffit archieve (no, I didn't know what stuffit was either) and actually turned 200k worht of files into a single 250k file. Plus I had to download a 5mb program to decompress the damn thing.

So the lesson here is (1) don't use proprietry compression utils like stuffit (2) don't bother compressing jpegs, the space savings, if any, isn't worth the trouble. Save your money and buy a bigger harddrive.

.Ray

alex wetmore wrote:

r00t wrote:

Does the compression affect the quality? I use WINRAR for
compression. If affected, do other compression programs alter
pictures differently? Is one proggie better than the other when it
comes to pictures?

No. RAR and Zip are lossless compression techniques.

They are also unlikely to compress the pictures very much. The zip
algorithm saved me all of 1k on a full resolution, fine quality
picture from the DSC-F707. JPEG is already a compressed format.

alex

SPT Regular Member • Posts: 173
Re: Question:Do you lose quality if you RAR/ZIP your pix?

.Ray wrote:

So the lesson here is (1) don't use proprietry compression utils
like stuffit

Looks like another Windows/Mac debate. FYI, Stuffit is THE way to go on the Mac... As far as I know, RAR and Zip are as "proprietary" as Stuffit, but they are compression formats you are more familiar with and for which you already have tools. When I send a compressed file (not JPEG...) to a PC-centric friend, I use Stuffit to compress in whatever format he/she asks for or has decompressing tools for.

(2) don't bother compressing jpegs, the space savings,
if any, isn't worth the trouble. Save your money and buy a bigger
harddrive.

I agree with you here.
SPT

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