Abstract: An improved record member is disclosed of the type having a sensitized surface including an oil soluble acid-reactant organic polymer and a colorless acid type mineral such as kaolin clay. Sensitized surfaces of the foregoing type develop distinctive colors when contacted with a normally colorless oil solution containing two chromogenic materials which react, respectively in different time sequence, with the polymer and acid mineral. In the improved member kaolin particles are encapsulated within the said polymer material, whereby said sensitized surface possesses better and more uniform marking qualities. A method for preparation of the coating composition utilized in the member is also set forth.