A new linear head is being developed, using Telegen Display Corporation's HGED technology, to expose Cycolor instant photographic media in a compact digital printer. Some of the design criteria used in the development of the new head to optimize the quality of the final picture are reviewed in this paper. The spectral characteristics of the red, green and blue phosphor emissions need to be matched to the spectral absorption characteristics of the corresponding photo-initiators employed in the microcapsules of the Cycolor photographic media to minimize exposure cross-talk. The intensity of the phosphor emissions also needs to be high to obtain the required print speed of 20 seconds. The selection of each of the phosphors needs to take both of these criteria into account. Specific details in the selection of the red phosphor system are provided.