I'm not exactly sure if I am using the right terminology, but when using the OSX color picker, you have the ability to store colors in your own personal archive. (see picture)
I recently did a clean install of my operating system and lost my palettes. Does anyone know where this data is stored?
In my investigation it seems the preferences are saved here:
~/Library/Colors/NSColorPanelSwatches.plist
It is my guess that this file would be overwritten on a clean install. However, if you want keep it, from here on out you may be able to copy it to a safe location. If you have a Time Machine backup, you may be able to dig through it and recover your previous version of this file.
If you named your custom palette, then in that folder would be a file similar to mycustompalette.clr
