Thank you Bill,
My next move will be to follow your advice #1 : to transfer the backups on a separate external drive. That in itself should free about 50 Go on my internal drive, which will be good news for it...
After that I will do some reading on "merging catalogs" because I would really like to simplify my structure with only one catalog.
But I will do some studying first.
Did I understand your advice properly?
jcs
Yes. I don't thing that all collections merge so if that is correct. First apply a keyword to all the photos in any collection that you care about. as I said earlier "COLLECTION_collection name". Also apply to all photos in each catalogue a KW "FROM_catalogue Name".
For collections that matched ones in he catalogue I was merging in to I simply added them to there respective collection.
For collections that were not in the master catalogue I made them from the collection KW.s.
(Tip: Use keystrokes:
*Select all the images for each collection KW. CNT/CMD "A"
*Edit the KW so you can copy it's name CNT/CMD "C'
*cancel edit
* Use CNT/CMd "N" To create a collection in the master catalogue.
*Past the KW in the name filed CNT/CMD 'V" y
*Select the check box to include selected photos
*Save
I had so many catalogues that I went a step further to make it quick and easy to see what each catalogue status. So that info would show up in badges in Grid View I created collections for the 'FROM_Catalogue Name". Using the same method. Now I can simply click on the badge to see which collections and from what catalogues the hoto is in.