This paper presents techniques for measuring a new set of parameters used to describe the image forming properties of positive photoresist [1]. Exposure is described by three optical parameters, A, B, and C, through which the process is modelled. Development is described in terms of a rate relationship R(M) between the rate of removal of photoresist in the developer and the degree of exposure of the photoresist. This set of functional parameters provides a complete description of positive photoresist exposure and development, and is the basis for the theoretical process models discussed in the accompanying papers.