In a method, a response sheet is provided to a user. The response sheet includes a machine-readable form having a number of response areas where the user can provide responses. After being received from the user, the response sheet has ones of the response areas marked by the user with a non-reflective fluid and also has other ones of the response areas being marked by the user with a reflective fluid. The received response sheet includes response areas marked with the non-reflective and the reflective fluid that were not marked in the provided response sheet. Responses provided by the user can be determined using an optical reading apparatus.
