Absolute basic question: does import duplicate photos?

[donheff]

I have never used Lightroom but got it when I purchaed a PS license.  I see lots of posts about disk space problems but none that describe what causes these problems.

I have 19K images filed as I like them in a bunch of folders.  I see on Lighhtroom that I can import without moving.  BUT, I do not want to duplicate the files as they already take up a fair amount of disk space.  Does the catalog simply build a DB of pointers to the files where they are or will it create copies, effectively doubling my disk use?

I am using LR Classic on Windows 11.  All image files (that I want to catalog) are in my One Drive Pictures folder.

[AxelMatt · Accepted solution]

With the default settings in Lightroom there are no duplicates are imported. Each photo is only available once in the catalogue. In the catalogue you can put the photos in one or more collections and so you can oranize the photos as yiou want and need.

Here you'll find more informations about catalogues: How Lightroom Classic catalogs work (adobe.com)  

[donheff]

Sorry Axel, I probably wasn't clear.  I am not concerned about importing duplicates - in fact I have some duplicates I created intentionally in separate folders.  What I don't want to do is create 19,000 new image files in the catalog that are simply copies of the 19,000 images on One Dirve.  I want my images to stay on One Drive.  My question is about the catalog -- does it create pointers to images where I have them stored or does it copy all of the images and create a new set of files in the catalog?

[donheff]

Sory again.  From the reference you posted I see that the catalog does create copies.  Thank you.

[dj_paige · Accepted solution]

If you import via ADD, the photos are left where they are and not copied anywhere else. LrC uses a database, which points to the files where they are.

If you import via COPY, then — can you guess what happens?

[donheff]

Thank you.  That is what I was looking for. Axel's reference page also answered that question.

[PhDJ]

When I want to import my pictures Lightroom marks all pictures as new, even if I have imported some of them.

How do I mark all of them as imported so it only selects the new ones next time?