Blotter Acid is a term for a particular method of delivering LSD into the bloodstream. Typically, blotter paper is soaked in or otherwise has a single dose of liquid LSD eyedropped onto it, then it is perforated into tiny (15x15mm at most) squares, one (or more!) of which is then placed in the mouth. The actual exchange of chemicals into the blood takes a few seconds. Other popular ways of ingesting LSD include gelcaps and liquid LSD.