Right, so I've been trying Lightroom, and robgendreau is correct. The catalog is not stored on the NAS, but I've been doing more research, and I think I understand that LR keeps their "database" on the mac and I can have the photos anywhere. So, I decided to get a simple external drive to keep the photos on that and will use the NAS as a backup so I don't take the network performance hit.
What I'm now trying to understand is the difference, if any, between keywords and tags in LR. I would like to be able to keep as much of the tags with each picture as I can in case I used my PC or anything else for whatever reason. On the mac, I can actually adds tags to a photo from the Get Info (Properties) window. But when I do, I don't seem them in LR. When I add a keyword in LR it shows up in the More Info section of the file properties. Is this the EXIF data?
I like to use NAS or the equivalent for storing finished photos that I want to display on other devices, share, etc. And also photos I am backing up or archiving. Both uses seem to benefit from the easier access on a NAS or in the cloud.
Keywords and tags can be the same, and serve similar purposes. But in the photo context we use "keywords" because of the IPTC standard, since that's what they are referred to in the IPTC standards. Fastidious users refer to "tags" when describing words tagged to files on computers, or posts, or whatever. On Macs, tags refer to words that are attached to files via what are called extended attributes in the file system itself; they were once sort of a hack via Open Meta, but since Mavericks have been incorporated into the Mac OS. But these are peculiar to the Mac filesystem. The really cool thing about IPTC keywords is that they can be written into image files and therefore are extremely portable; if you can read the image file on a device you can probably read keywords. In the case of RAW files, they can be written to XMP (a sort of XML developed by Adobe, but an open standard) as sidecar files.
Whew. I love tags and keywords. So here is perhaps too much info.
When you use Get Info on a file, or "tags" in a dialog box, or "tags" in various programs, you are looking at Mac OS system tags. Not photo keywords. You could use say "mom" as a keyword and a tag, but they reside in different places, are accessed differently and apply to different files.
Tags can be applied to
any file, but do NOT travel with that file outside the Mac filesystem, with some exceptions. You can find them with Spotlight searches. You can apply them to darn near anything; I use them on email, photos, Word documents, folders, etc.
Keywords can be applied to
certain image files (JPEG, TIFF, etc). Since RAW files aren't per se "images," and proprietary, you usually can't (or shouldn't) write the keywords INTO the RAW files, so they are written as XMP sidecars. Keywords can generally be accessed by photo software, but (and many people don't realize this) also by Spotlight. Cool, no? When you do a Get Info on a jpeg with keywords, you'll should see the keywords listed under "more info." But you can't apply them. But you will see a "tags" box where you can apply tags. See below for an example. That "more info" also can contain all sorts of exif info, which is sorta like automatic keywords (so you don't need to add camera model, e.g.). Worth exploring.
If keywords are written to files, then off they go with the file. When you peruse the IPTC standard you see what a great thing this is: designed so that say a sports photographer can add all the info for caption, sorting, etc etc so just the picture has all the editor needs. Check out Photo Mechanic if you want to see how far this goes. A DAM like Aperture or LR can store the keywords WITHOUT writing to the file, which can be useful, but I do it by default. It means most of my organization is independent of photo software.
You can see how the metadata keywords are displayed in LR below.
One big difference in LR (or other DAMs) is that it can do
hierarchical keywording. This is super useful, since it means you don't have to keep entering the upper level words, like "animals" and "mammals" when you enter "dog." It also means you can design hiearchies to mimic your collection or folder structures, and that travels with the photo files. These are basically the same information:
Finder: /Animals/Mammals/dogs
Keywords: Animals>Mammals>dogs
System tags have no such hierarchies.
Note that LR writes the HIERARCHY into XMP in metadata; many photo applications don't. It takes the form "Animals|Mammals|dogs." Hierarchies otherwise are written into keywords as "Animals, Mammals, dogs" which would be indistinguishable from "dogs, Animals, Mammals." LR's method makes the hierarchies portable, but I don't think it's an IPTC standard. (Put a string with keywords separated by "|" (pipe character) into the keywords field in another application, say Graphic Converter, and LR on import will make that a hierarchy, BTW.)
LR users have posted lots of info about keywording online. It's extremely powerful. A savvy LR user told me to use keywords for permanent info I wanted with the photos, like who is in it, location, copyright, etc etc. And to use collections and collection sets for transitory info, like "To Be Edited," "For publishing to Flickr," "Lens test," "Portraits," etc. I love the way that works; YMMV.
Finally, I find it helps to think of tags and keywords as sort of a hierarchy themselves. A "mom" tag really means "any Mac system file>mom," while a "mom" keyword really means "image file only>mom." This rule can mean that searching produces different results: search "mom" tag might only get emails to mom if you didn't
tag photos of mom; the converse for a search on the keyword "mom." But you get both by a keyword+tag search on "mom."
Whew. Sorry you asked?
