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Author Topic: Compressing large amounts of data  (Read 2515 times)

Offline Frances144

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Compressing large amounts of data
« on: September 11, 2011, 09:47:44 AM »
I have some large folders full of RAW photos I want just archive and keep on a dvd preferably.

I tried Disk Image in Utilities and managed to get a 12.58gb folder down to a disk image of 12.32gb. That is not what I call compressed. It is just very slightly smaller.

I tried using Toast Titanium and got it down to 12.29gb - still not very compressed.

Where am I going wrong.  I thought Disk Image made large things smaller.

If it is not that method, what can I use to get a large folder squeezed onto a dvd?

Compression doesn't really equal anything smaller imho.

All thoughts welcome and all help appreciated xx
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Offline Xairbusdriver

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Compressing large amounts of data
« Reply #1 on: September 11, 2011, 10:02:09 AM »
Disk Image is an image of a disk, there's no compression being use, AFAIK. It's simply a way to put stuff in a file that can be downloaded easily and 'mounted' on your machine just like a physical disk. It' basically a 'virtual' disk.

But the OS does have a compression function. It used to be called "Archive" but I think it now is labeled "Compress." Look in the File menu in Finder. It's super simple and pretty fast. Just select a file or a group of the the normal way and then use the Compress/Archive menu item. The compressed file will be labeled simply Archive.zip. I highly recommend editing the name to something much more meaningful!! laughhard.gif

Once you have all the file compressed, you can burn them to a CD/DVD or a disk image. Uncompressing is as simple as double-clicking an archive/zip file.

But you should be aware that many files/documents simply won't end up much smaller. Audio/video/some images formats are already in a compressed format and trying to compress them further won't help. Those types of files can sometimes be converted to a different format to make them smaller. YMMV.
« Last Edit: September 11, 2011, 10:04:56 AM by Xairbusdriver »
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Offline Frances144

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Compressing large amounts of data
« Reply #2 on: September 11, 2011, 10:30:59 AM »
Thanks.

For some reason, I thought Disk Image did compress.

I don't really want to convert the data into a different format, ie jpeg because I will lose quality and I want them to convert back to RAW when uncompressed.

Trying out "Compress" !
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Offline Frances144

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Compressing large amounts of data
« Reply #3 on: September 11, 2011, 11:00:02 AM »
Well an 11.42gb file compressed to.....



......



......


a tiny teensy 11.18gb file.

That is not a compressed file at all.  That is one that is slightly less large imho.

Ho hum - back to the drawing board.
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Offline Paddy

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Compressing large amounts of data
« Reply #4 on: September 11, 2011, 11:09:07 AM »
Frances, RAW images are already compressed, according to this (which would explain your lack of progress so far):

http://www.modelmayhem.com/po.php?thread_id=472900

This app claims to compress RAW images 20-60% without loss:

http://www.rawzor.com/photo/

Discussion of Rawzor: http://photo.net/digital-darkroom-forum/00T3an

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Offline Frances144

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Compressing large amounts of data
« Reply #5 on: September 11, 2011, 01:52:19 PM »
Thanks, Paddy.

I did download Rawzor only to find it said I needed a more up-to-date version which I could find nowhere on their site.  I emailed them but have received no answer, so am none the wiser.

Still, I shall keep on thinking.
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Offline Xairbusdriver

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Compressing large amounts of data
« Reply #6 on: September 11, 2011, 02:05:37 PM »
I'm not sure you'll get much comfort in 'compressing' images when keeping the original format. I don't have a camera that creates RAW, so I have no experience with them. But you may have good results from the app Paddy linked to. OTOH, you might also try converting to tiff or even png (not to mention psd) and see if that makes sizes smaller. Of course, none of those formats would probably save all the data from RAW. sad.gif As I said, images/video/audio don't make good candidates for compressing without changing formats. Sorry. Maybe you should just which to working with text!!! laughhard.gif
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Offline Frances144

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Compressing large amounts of data
« Reply #7 on: September 11, 2011, 02:08:04 PM »
Ok, I give up.

I am now going to buy another External HD.

I have a spare firewire port, I think but want one that could be USB too if that was possible.

Any recommendations?

I do NOT want it to back up automatically, but just let me drag and drop for folders to the ext HD without buzzing away or doing its own thing.

1tb or 2tb too.

I quite like the Western Digital ones. They look good value for money.
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Offline Xairbusdriver

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Compressing large amounts of data
« Reply #8 on: September 11, 2011, 04:53:38 PM »
Nothing backs up automatically, that I know of. laughhard.gif

After my experience with my <2TB Seagate>, all I can say is to be absolutely positive that the drive is absolutely guaranteed to work in an external enclosure. The only other recommendation is to get one with the largest cache and the longest warranty.

The drive, itself, couldn't care less about what I/O interface you use (FW/USB/E-SATA/Pony Express/etc.). That's a function of the enclosure and just about any combination you can think of is available. I will say that FW is generally less popular but more expensive than any of the others (except, maybe E-SATA). I'm sure many will offer specific enclosures to you, I'd only recommend buying from a known quality reputation company. In other words, not eBay and only after extensive research from an Amazon 'dealer.' wink.gif
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Offline Paddy

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Compressing large amounts of data
« Reply #9 on: September 11, 2011, 08:32:05 PM »
Frances, get a Western Digital (Caviar Black) a Hitachi or a Samsung, and put it in an enclosure yourself. That way you get a decent drive with an excellent warranty and none of the oddball software/partitioning that sometimes comes with fully assembled drives.

I like the Macally drive enclosures, or Vantec. For this sort of backup, save yourself some money and just get a USB enclosure. Speed isn't really an issue when you're just doing occasional backups manually - for that reason you can also consider the "green" drives.

I'm linking to NewEgg because of the customer reviews - lots of 'em. You'll have to find a UK dealer, of course, but the model numbers will be consistent, I think.

http://www.newegg.com/Product/Product.aspx...N82E16822136284
http://www.newegg.com/Product/Product.aspx...N82E16822152185

Anyway - more here: http://www.newegg.com/Product/ProductList....amp;PageSize=20

Look for drives with an established track record and a comparatively low number of "one egg" reviews - and a high number of 4 and 5 egg reviews. I typically aim for something where 80% or more of the customers have been happy (ie: 4 or 5 eggs). Hasn't failed me yet. smile.gif
« Last Edit: September 11, 2011, 08:32:53 PM by Paddy »
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Offline dboh

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Compressing large amounts of data
« Reply #10 on: September 12, 2011, 06:25:30 PM »
Can't Frances save them as TIFs, which would be much smaller? I've always been told they were lossless.
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