I was making a mini-album for a friend's birthday, and wanted to include a scan of a newspaper article that  featured the two of us making a fund raising quilt back in 1990.
I had kept a couple of copies of the article (my 15 minutes of fame) as well as a copy that one of my daughter's teacher had laminated for me at the time.  Wouldn't you know it--they were all yellowed the same amount.  Including the laminated copy.  Hmmm.  I had heard that laminating would protect the article, so I went to my expert to find out why it looked so bad.  That expert, a chemical engineer and former printing industry professional, (who also happens to be my husband, Doug) told me that the lignin in the newspaper would turn yellow even though it was not exposed to oxygen.  He further explained that even if you spray your newspaper article with a de-acidification spray (i.e. Archival Mist), you are not affecting the lignin content, and it will not prevent the paper from turning yellow.  What spraying and laminating will do, however, is protect the other elements on your page from being damaged.
My advice?   Scan your article and print it on acid free paper to use in your Scrapbooks.  Be sure to also include the date and the name of the Newspaper.  
The laminated  copy is on the left.