trying to understand relationship between raw, jpg and xmp

[cherietb]

Can someone please walk me through the relationship between the original raw, the exported jpg and the sidecar file.

1. I first make changes to original raw which presumably results in raw + xmp

2. I then export to jpg.

so now i have 3 files I can see in Finder. Is the xmp still tethered somehow to the jpg? If I send the jpg to someone else via email, they will see the jpg file with changes, right?

Also, I have checked "Include develop settings in metadata inside jpg, tiff, and psd files" and "automatically write changes into xmp"

If I didn't have these checked, and emailed the jpg to someone, would they see the changes? then I would keep seeing these little exclamation points on my thumbnails. I'm very confused. Thanks in advance for the input.

cherie

 

[Denis de Gannes]

The xmp file is only relates to the raw file. The exported jpg will be fine to e-mail.

 

[Brad Snyder]

Also, I have checked "Include develop settings in metadata inside jpg, tiff, and psd files" and "automatically write changes into xmp"

If I didn't have these checked, and emailed the jpg to someone, would they see the changes? then I would keep seeing these little exclamation points on my thumbnails. I'm very confused. Thanks in advance for the input.

Cherie, What Denis says is correct.

Taking it further, I think I understand the source of your confusion. You need to realize that JPGs that are 'inside' of Lr have key differences from JPGs 'exported' from Lr.

I hope the following clarifies, rather than confuses.

Think of Lr as a magic box, which contains all of your images, and their adjustments, and non-image metadata, and organization, etc. This information is maintained automatically inside the Lr database, and most of it can also be stored in or with the original image file.

Unfortunately, the rest of the software world doesn't understand Lr's system, and in order to produce files for sharing, or printing, or emailing, etc, the images have to undergo an 'export' process. In this way, your original raw file and its associated XMP adjustment metadata, are converted to a plain, ordinary JPG file, which looks just as it does in Lr, only it's compatible with everyone's software.

That setting that you mention in your post, (Include Develop settings .....) actually applies to a different situation. Suppose instead of a raw file type, you imported JPG, TIF, or PSD files(these are usally called RGB file types). Lr will handle these similarly to the raw types, but instead of creating (optionally) an XMP file, it can save the XMP data inside the RGB file type.

Again, we have a compatability problem, because even tho' your original image may be a JPG file, with Lr's XMP changes embedded, other software still doesn't know what to do with it. For that, you again have to *export* the JPG, so that you now have two JPG files. One that's 'in' Lr, with the secret XMP code, and one outside of Lr which everyone else can read.

Geez, why bother with something so complicated? Because JPG has a severe shortcoming, in that everytime you save a JPG file, the repeated file-saving compression begins to affect the image quality. Lr's system allows you to make as many saves as you like, while preserving the uncompressed original.

These are fairly subtle distinctions, but they're critically important as to how Lr interacts with your files.