Section 1418 Of Article 2. Means Of Authenticating And Proving Writings From California Evidence Code >> Division 11. >> Chapter 1. >> Article 2.

. The genuineness of writing, or the lack thereof, may be proved by a comparison made by an expert witness with writing (a) which the court finds was admitted or treated as genuine by the party against whom the evidence is offered or (b) otherwise proved to be genuine to the satisfaction of the court.