.tif Compression?!

[BrianEE93]

After I process my RAW images I save them as TIF files. In PS I am given the choice of no compression or LZH, ZIP and JPEG. Am I correct in using LZH for lossless compression? I don't like the idea of compressing the file with JPEG on my really good shots but would like to save some hardrive space and backup time if LZH TIFs are lossless. Is this the case? Would anyone suggest using a different file type or compression?

Thanks,

Brian

[Longwatcher]

I found I was out of date on TIF compressions, but the best mathematically lossless compression you can expect to achieve is 8:1, with 4.3:1 being more realistic. That said TIF LZW is very good. And "Jpeg 2000" is supposed to have a lossless compression that is better, but it has not been adopted very widely so you may have supportablility problems in the future.

For archiving your shots, I recommend uncompressed TIF, even if it does take up more space. However, If you are 99% certain you will not be editing the image in the future then save as JPEG at highest quality/lowest compression setting (which should be 10:1). Even if you do need to go back some day, the loss should be acceptable to one level of save. It is generally better though if you shot in RAW to just archive it in RAW as this will take up more then jpeg, but should eb less then compressed TIF. An alternative is to get Adobe's DNG RAW converter and use that as with hope DNG will be adopted as a standard (I hope).

Just my opinion and what I remember,

[BrianEE93]

Thank you for your reply. As far as you know is TIF LZW lossless? I am okay with storing all my pictures as TIF but if LZH is lossless then that just saves a little space. I guess I should consider saving the RAW images. I guess Adobe Camera RAW inbeds your settings into the file and then you can save it back as RAW? I have been using RawShooter lately and it just saves your settings in a separate directory. The problem with this is that I am using Elements 3.0 for my organizer and backup program. It won't know to do anything with that separate directory.

I will have to look into it a little more.

Brian

[Jesper]

LZH is a compression algorithm similar to the ZIP algorithm, and it's lossless.
For archiving your shots, I recommend uncompressed TIF, even if it does take up more space.Why? You don't loose any data when you use a lossless compression algorithm.

[tim]

I guess Adobe Camera RAW inbeds your settings into the file and then you can save it back as RAW?

The RAW file is never changed. The settings you change (exposure etc) are saved in the PS CS database, or if you change a setting, they can be stored in an .XMP file in the same directory as the photo. If you make any changes in photoshop proper you should save the file as a TIFF or PSD.

[Longwatcher]

LZH is a compression algorithm similar to the ZIP algorithm, and it's lossless.
Why? You don't loose any data when you use a lossless compression algorithm.

You don't lose data, but fewer software are supporting the compressed version. So maybe more of a problem recovering in the future then straight TIF.

[PacAce]

You don't lose data, but fewer software are supporting the compressed version. So maybe more of a problem recovering in the future then straight TIF.
And that's the reason I never compress my TIFF files. :)

[Rob612]

Other option, keep the JPG images and store directly the RAW (except for those where you did heavy PS). You'll need extra work in case of redoing an image, in this case.

[BrianEE93]

Thanks for the responses. I guess for my really good pictures I will just save as uncompressed TIF and for my so so pictures I will save as a high quality JPEG. Hardrive space is no big deal since it is really cheap and I backup to a second drive. I also like to backup to DVD and storage it at my mother-in-law's house. The DVDs are the slow part. I guess I will do incremental backups.

Brian