8 Replies Latest reply: Apr 25, 2009 10:38 PM by Ian Lyons RSS

    no lzw for 16 bit export

    Scooby007 Community Member

      Wondering why LR doesn't offer LZW compression for 16 bit tiff export, since PS offers it when saving as for 16 bit tiffs. Saving with LZW is faster than with ZIP in PS

       

      Anyone see a downside to exporting as 16bit tif with ZIP, then opening is PS, editing, and then saving as with LZW? Upside is it's a faster save

       

      BTW, I export then open in PS from disk to edit. I don't like the send to PS from LR method, I'm not interested in going that route.

        • 1. Re: no lzw for 16 bit export
          JimHess-8IPblY Community Member

          Even if Lightroom did use LZW compression I probably would not use it.  I occasionally use Noise Ninja to apply noise reduction, and it doesn't seem to accept images that have been compressed.  From what I have seen, LZW compression doesn't seem to make that big of a difference anyway.

          • 2. Re: no lzw for 16 bit export
            Scooby007 Community Member

            Interesting, I did three saves in PS of a 16bit tiff

             

            none - 56mb

            lzw - 67mb

            zip - 52mb

             

            tried it a couple more times and the lzw was bigger again

             

            it does compress well for 8bit tif, guess I'll ditch any compression for 16bit.

             

            btw if you choose zip in PS it tells you that is has compatibility issues and is slow to save. odd that they would make it the only option for compression in LR

            • 3. Re: no lzw for 16 bit export
              Scooby007 Community Member

              and saving with no compression is definitely way faster

              • 4. Re: no lzw for 16 bit export
                Ian Lyons ACP/MVPs

                Compared to Zip LZW is not particularly good at compressing photographic images, and is especially poor when they're 16 bit. Also, LZW doesn't handle noise all that well. It's not unusual for such images to end up weighing in larger than the original.

                • 5. Re: no lzw for 16 bit export
                  Scooby007 Community Member

                  Thanks Ian, I'm glad I ditched it. The saves are going much faster now too.

                   

                  Question is, for a large batch of 16-bit tiffs that I've already exported from LR using zip, and am now bringing through PS one by one, should I re-export them from LR without compression (for the ones I haven't already processed in PS)? As it is I'm just opening them, editing, then saving as and choosing no compression

                   

                  BTW, I know this a LR forum but for anyone that cares, I've just discovered that switching to the "use OS" mode in the "save as" dialog makes the process of "saving as" for large files quite a bit more responsive and quicker

                   

                  Thanks

                  • 6. Re: no lzw for 16 bit export
                    Ian Lyons ACP/MVPs

                    The compression is lossess, so going back and resaving the files isn't going to gain you any extra data. Therefore, it's probably more efficient to keep doing as you are now with existing files.

                     

                    The reason that OS mode is faster is because it's not trying to hook into the Version Cue client that your probably not using anyway (PITA as it is in a non multi user environment)

                    • 7. Re: no lzw for 16 bit export
                      Scooby007 Community Member

                      Thanks, was assuming no data would be gained, but wanted to be sure no compromises on IQ in any way with jockeying around from compressed to uncompressed. Saving as and uncompressing is offering a big benefit in much faster saves. I feel better that the files will be more universally compatible too.

                      • 8. Re: no lzw for 16 bit export
                        Ian Lyons ACP/MVPs

                        Not that it's going to change anything written above, but to avoid future confusion - LZW is available when you choose to export as 8-bit. I't's not available for 16-bit for the reasons I outlined previously.