part of compound eye photoreceptor development R1/R6 cell differentiation R1/R6 development GO:0048053 The process whose specific outcome is the progression of the R1 and R6 pair of photoreceptors in the eye over time, from their formation to the mature structures. R1 and R6 are paired photoreceptors that contribute to the outer rhabdomeres. An example of this process is found in Drosophila melanogaster. biological_process