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LZW Compression


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#1 Simon K.

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Posted 31 January 2003 - 03:58 AM

Hi,

I read, that lzw compression in tiffs is loss free. Is this right and are there any other disadvantages using it?

Bye
Simon

#2 markh

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Posted 31 January 2003 - 02:22 PM

Lzw is indeed lossless compression. It is used with TIFF & GIF files and compresses the files by up to 50% thereby saving on storage space. I would say that if you are utilising TIFF instead of RAW format & you have facilities to use it then DO use it! As far as I am aware there are no disadvantages to shout about, apart from the fact that not all camera makes use it!

Welcome any other comments on this!

Hope this helps though.

Mark
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#3 james

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Posted 31 January 2003 - 02:30 PM

When you convert RAW to TIFF, then open the TIFF in Photoshop, then go to save it, you can apply LZW compression.

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#4 markh

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Posted 31 January 2003 - 02:43 PM

Thats interesting James. I cannot do this with PSP. It only offers TIFF save as feature not LZW. I will now get on the Digital Workshop forum & put this to them for suggestion.

If I knew Photoshop were developing compatibility with ORF files (Oly RAW) I,d probably buy it!!
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#5 james

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Posted 31 January 2003 - 02:57 PM

My guess is that the Adobe guys are working on the Canon, Nikon, and Fuji RAW files, as that's what most of the "serious folk" use. Oof, gotcha! Perhaps they'll do the Olympus next.

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#6 wetpixel

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Posted 01 February 2003 - 02:21 AM

My batch processing slows down considerably when I use LZW with TIF files.

bah!

disk is cheap these days, right? :) I just set up a 400GB NAS box for backups. It was about $900! not bad. :) (Promise Tech. makes a new low-end cheapie NAS box. It's loud as hell, though. I may have to find a closet to stuff it into.).
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#7 james

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Posted 02 February 2003 - 06:12 PM

OK, I'll be the one to ask: What's an NAS box?

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#8 craig

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Posted 02 February 2003 - 06:31 PM

Network Attached Storage. It's a box you attach to your network that provides ready to use disk storage with a minimum of fuss.
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#9 sethgold

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Posted 02 February 2003 - 06:51 PM

OK, I'll be the one to ask: What's an NAS box?

Cheers
James

Its a self contained piece of hardware for network storage. It has a network interface, an embedded OS, and an embedded web server for administration. It runs on simplified hardware; no monitor, keyboard, etc. You pretty much just plug it into your network and a power source.

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#10 wetpixel

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Posted 03 February 2003 - 12:12 AM

The funny thing is -- these days a stripped down DELL box during their sales is often less than a NAS box. My workhorse DELLs were something like $700 shipped (I added more RAM and disk space), and they are 2.4Ghz P4s. Amazing, really, how cheap they can be!
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#11 craig

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Posted 03 February 2003 - 07:17 AM

For work (unrelated) we need machines with 64 bit, 3.3V PCI. Last guy that needed two machines bought them from Dell for $350 a piece. How stupid is that!

I like the little Shuttles, too. You can put two drives in them easily.
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#12 gothamboy2000

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Posted 13 February 2003 - 12:28 PM

LZW is lossless and this is true no matter what format you apply it to. However, some data will compress better than others.

The only downside, of course, is that you don't get the 20:1 compression ratios you get with JPEG. I'm at a bit of a disadvantage in this conversation since I have yet to successfully take an underwater photo that looks any different compressed with even moderate JPEG compression.

As for the camera raw extraction, again, we have publicly shown this plug-in though specific support for cameras has not been mentioned.

I'd keep an eye on Adobe.com in the coming days...


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#13 markh

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Posted 13 February 2003 - 12:53 PM

Daniel, as our resident Adobe man can you help with this one. I use PSP & recently downloaded the Oly PS plugin and applied it to PSP. I was informed by Digital workshop the filter is compatable with PS & PSP. Is this true? I have loaded the plugin into PSP & it visibly recognises together with identifying the ORF file. However, when I try to open the file it dumps me out of the programme. Can you shed any light on this?

Mark
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#14 gothamboy2000

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Posted 05 March 2003 - 06:48 PM

Hmm... Much as I love the Jasc guys, I don't know that much about their app and its support for Photoshop plug-ins. As just about anyone can tell ya, the word "compatible" has quite a range of meaning.

If Photoshop is too big a financial bite, you might look at Elements. Elements is built off of the Photoshop code base so compatibility is far less of an issue.

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#15 markh

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Posted 06 March 2003 - 04:42 AM

Thanks Daniel. One step ahead, PS 7 is on its way to me.

Mark
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