-rw-r--r-- 1 mycroft staff 761044992 3 Jan 15:30 Lightroom 5 Catalog.lrcat
The latest backup shows that it used to be much smaller:
-rw-r--r-- 1 mycroft staff 565186560 30 Dec 19:13 Lightroom 5 Catalog.lrcat
What happened in this time interval?
Well, I did only one thing, I created a print collection that produces one 4x4 "mosaic" page,
and I used a large graphical identity plate (actually LR warned me that the file was too large...).
Then I duplicated the collection and converted it to a 2x8 layout.
So the first thing that I (un)did was to delete the identity plate and then optimize the catalog:
here's the before and after.
-rw-r--r-- 1 mycroft staff 723652608 3 Jan 17:04 Lightroom 5 Catalog.lrcat
-rw-r--r-- 1 mycroft staff 685568000 3 Jan 17:06 Lightroom 5 Catalog.lrcat
However, a copy of the identity plate was still stored in the catalog as a "custom plate"
in the print collection itself. I replaced it with a text-only logo, and voilà:
-rw-r--r-- 1 mycroft staff 609447936 3 Jan 17:14 Lightroom 5 Catalog.lrcat
Still not quite the original size, but much better.
Its surprising however that identity plates are stored in the catalog, but they are NOT exported.
There's a table in the sqlite catalog, called Adobe_namedIdentityPlate that you need to import manually from the terminal:
sqlite3 catalog.lrcat .dump Adobe_namedIdentityPlate > plates.txt
(edit plates.txt -- see below)
sqlite3 exported_catalog.lrcat .source plates.txt
You need to remove the "CREATE TABLE" statement from the text file before re-importing:
CREATE TABLE Adobe_namedIdentityPlate (