compression of RAW files

[KenN]

Hi,

My workflow goes like this:

- download all RAW files to a folder
- go through, tagging keepers in YarcPlus
- convert to linear 16
- Linear Sharpen -> .PSD
- touch up / adjust by hand as needed

Now, I'm also a nut for keeping all the original raw files. No reason, except sometimes somebody says "if you just did this", and it turns out to be something I have to start with the raw file to do.

Trouble is, a typical session, like yesterday afternoon's portrait session yields 4GB of data.

I'm interested in compressing my RAW, TIFF and PSD files prior to writing them to the DVD backup. I leave a final archive of high res JPG on the DVD for browsing, but would welcome a signficant reduction in the space needed so I can squeeze more onto a DVD (5GB isn't enough!).

However, as expected, when I tried with winRAR or WinZIP the results were bigger.

Any tips on lossless compression of RAW and PSD files?

Regards,

Ken N.

[lord.hypnos]

RAR has better compression than ZIP, and there are few things you can do to squeeze a few more bytes out of the file sizes. When creating RAR files, select "create solid archive" and select "best" for the compression method (although "normal" usually produces close to the same filesize and is a lot faster).

One way to save space is to turn off "maximize compatibility" when saving Photoshop PSDs. Edit>Preferences>File Handling

If you are compressing JPEGs you want be able to squeeze them down much more since they are already compressed.

There are other compression formats available, notably ACE, and you could try different compression formats to see which gives you the best results. I'd recommend PowerArchiver as it supports "ZIP, CAB, LHA (LZH), TAR, TAR.GZ, TAR.BZ2, BH, RAR, ARJ, ARC, ACE, ZOO, GZ, BZIP2, XXE, MIME, and UUE file formats."

http://www.powerarchiver.com/download/

[Roger_Cavanagh]

Ken,

I doubt you'll be able to get much extra space by trying to compress raw files. They're already in a lossless, compressed (and proprietary) format. I entirely agree with you about keeping them.

Also do you need to save every PSD? Unless you have done some serious editing that would be difficult to reproduce, why not just save a JPG version?

Another question is does the final PSD have to be 16-bit? If all edits are complete, there is little to be gained by staying in 16-bit. That's a big chunk saved for each file.

Regards,