Authentic Rowling Signatures
Rowling's signature has changed drastically since the Harry Potter books were first published. Of course, the earlier examples are much rarer and much more valuable. That said, there's much that goes into a signature's value. Knowing the many different styles of Rowling's hand is important when buying signed pieces to ensure that you're getting your money's worth.
From a 1997 1st print, 1st edition Philsopher's Stone, owned by Peter @thePotterCollector
1st Print, 1st Edition Bloomsbury Chamber of Secrets (Bloomsbury Bookplate), owned by me :) Notice the dots between the J and K have fallen out by this time.
1st Edition, 2nd Print Sorcerer's Stone (from 98 US tour); owned by me currently
1st Print, 1st Edition Sorcerer's Stone, 1998 US Tour; owned by me
Purple Bloomsbury Azkaban Proof; signed to dedication page; owned by me :)
22nd Print Sorcerer's Stone, US 1999 Tour; formerly owned by Peter @thePotterCollector
22nd Print Sorcerer's Stone, 1999 US Tour; formerly owned by me :)
from an 8th Print Sorcerer's Stone, 1999 US Tour
Later print Bloomsbury Philosopher's Stone Softcover; 1st part of a 3part signed/dedicated "To Chloe" set; set owned by me :)
2003 and later
1st Print, 1st Edition US Harry Potter and the Goblet of Fire, signed in the UK; owned by me :)
from an adult UK Edition Harry Potter and the Order of the Phoenix
This bookplate bears the same cover art as that from the book. Most of the signed UK Half-Blood Prince books were signed using this bookplate; flat signed books do exist, but they're quite rare.
Rowling's signature has changed drastically from 1998 to 2007!