Why does File- Export process jpgs where I have made no changes?

Question

Hi, I'm new to Lightroom.  I would like to make LR my photo management software of choice for managing my huge personal collection of photographs.  I've flagged keepers and tagged photos accordingly: Food, people names, etc.
What I would like to do now is find all photos marked with the tag "JapanVacation2009" and export them to disk so I can bring them to a friend's house and share them.  When I click File->Export, I see that even though I've make tone and exposure changes to less than 1% of my my photos, LR reprocesses every photo!
What I want is that for photos where I have made some kind of change, yes, please process and create the new version of the photo.  For photos where I have made no change except for adding tags, please, please, just copy the file into the export directory!!! It's faster AND I really didn't want my photos reprocessed.
I am sitting here waiting for these files to be exported (reprocessed)-- this is taking forever!  I generally take my photos in jpg because I'm really going to make very few changes to my photos-- I know that I could take them in RAW, but I find this inconvenient for my workflow.
Please help. If I can't find a resolution, I'm going to have to investigate something like Picasa.
LR gurus, what do I do???

Answer 1

Folders are irrelevant to LR as an organisational tool. LR will search, create collections or smart collections based on whatever criteria you set.It is a very quick and effective organisational tool once you have learnt how to use it.
When exporting from LR to a lossy format such as a jpg if the file is already compressed and you re compress it then this will result in further loss of quality. That is always the case when using JPGs. If you export at 100% ( no further compression) then no loss of quality will occur due to compression, but obviously re processing a processed 8 bit format such as a JPG will always result in some quality loss. If you have made no changes to the original JPG in LR and then export it at 100% then LR just produces a copy of the original and no loss of quality will occur.  JPG should really be treated as a finished format and no further processing applied. If you wish to process your images then retain the RAW file, or if scanning, scan to a 16 bit file such as TIFF to minimise any quality loss as a result of processing.
Exporting times are very quick from LR as long as your machine is well set up and has enough RAM. 600 images with few changes dependent on the size of the image would only usually take a few minutes to export to a disk dependent on the speed of the disk. Obviously if you are exporting to a slow hard drive, to things like DVD's and CD's, have little RAM or lots of other applications running in the background this can slow things down, there are lots of tips around here and elsewhere on how to set up your computer to get the best out of LR.