Re: RAW VS JPEG

On Mon, 17 Dec 2007 14:35:11 -0900, Floyd L. Davidson <floyd@xxxxxxxxxx> wrote:
nospam@xxxxxxxxxxxxxxxxxxx (Keith) wrote:

Even better use Lightroom or Aperture and you work non-destructively
directly on the RAW image, with no jpeg or tiff duplicates clogging up
your storage.

You aren't working "directly on the RAW image". It
*does* convert it to an image format (almost certainly
not JPEG, but it might well be a TIFF variant) before
editing. Whether you save that image or not is perhaps
a reasonable option, but others might well do whatever
it is that you don't, and both are reasonable.

That's not right. Aperture (and Lightroom, I believe) generates a screen
image in realtime based on the RAW file plus a short (few kb) XML file
specifying all of the filters and transforms etc. that are being
applied. The realtime rendering is primarily handled by the GPU rather
than the CPU so I suppose you could say that it's been "converted" to a
chunk of data sitting in VRAM, but that seems like a stretch. You can
certainly export that data in TIFF file if you want, but you don't have
to.

Aperture generates a (jpg) preview image for each RAW file, but you can't
do any edits on that; it's for thumbnails and inter-application sharing
of the photo library and so forth.

To be specific, drilling down inside the Aperture library, here's what
one image looks like on the disk (each image has a directory of this
sort):

dmsilev% ls -l
total 20712
-rw-r--r-- 1 dmsilev dmsilev 10554548 Dec 15 12:15 DSC_2008.NEF
-rw-r--r-- 1 dmsilev dmsilev 1337 Dec 15 13:07 DSC_2008.NEF.apfile
-rw-r--r-- 1 dmsilev dmsilev 488 Dec 15 13:07 Info.apmaster
-rw-r--r-- 1 dmsilev dmsilev 18449 Dec 15 13:07 OriginalVersionInfo.apversion
drwxr-xr-x 3 dmsilev dmsilev 102 Dec 15 13:08 Previews
drwxr-xr-x 3 dmsilev dmsilev 102 Dec 15 13:08 Thumbnails
-rw-r--r-- 1 dmsilev dmsilev 20313 Dec 15 13:14 Version-1.apversion

You see the original NEF file and 4 .ap* files, which are XML files
containing metadata and the applied filters/etc. Previews contains the
jpeg previews, which clock in at ~600 kB each with the settings that I'm
using. Thumbnails contains 10 kB jpeg versions. No TIFF or anything
similar anywhere in the directory.

-dms
.

Relevant Pages

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