Note for myself for the future.

To copy a DVD that I’ve made in iDVD after I’ve already deleted the source material and DVD project files:nn

  1. Insert the master DVD.
  2. Fire up Disk Utility.
  3. Select the DVD in the Source menu.
  4. Click the New Image button in the Toolbar.
  5. In the dialogue sheet that follows, name the disc, select “CD/DVD Master” from the type list, and “none” for the encryption option.
  6. Rip the image, then burn it to a blank, also using Disk Utility.

That’s it.