If you have added or edited light sources in either the catalog light source library or project-specific light source library, you can save the custom light sources to the external light source library file (Lights.llb). You can then import the customized light sources from the library file into any light source library, whether that be the catalog light source library or project-specific light source library. The library file basically acts like a shuttle between libraries.
You can save light sources to the default light source library, or create a new library to save them in.
To save light sources to the light source library file:
Access the light source library. How to
In the Light Sources dialog, click Transfer.
In the Open dialog, select the Lights.llb file (or whatever file you want to save to), then click Open.
Tip: You can create a new library file if you want by entering a name in the File name edit box.
In the left pane of the Transfer dialog, select the light source you want to save, then click Export Item. To export the entire list, just click Export All. The library file is updated.
Click OK.
If you want to import the custom light sources into your catalog light source library or the project-specific light source library, see Importing Light Sources from a Light Source Library File.