A composition of a getter and a field emission display using the same are disclosed which are capable of improving a degree of vacuum and a gas rejection capability by performing an activation process by using a getter that can lower an activation temperature. Each of a plurality of improved openings 62A of the deposition mask 601 has a protruding opening portion 64, and is formed so that the opening amount at an end in a lateral direction is larger than that in a central portion in the lateral direction. In some instances, the techniques encode each nonzero coefficient of a coefficient vector of the enhancement layer without knowledge of any subsequent coefficients. Each printhead module includes a cover member with ink conduits extending through the chassis into respective ink reservoirs. The dust hole is sized to permit the exit of debris entrained in a flow of cooling air from the airfoil.