Papanicolaou’s solution 2a Orange G solution (OG6) - for cytology, is a ready-to-use solution used for human-medical cell diagnosis and serve the purpose of the cytological investigation of sample material of human origin, for example, cervical smears. Papanicolaou’s technique is the most used staining procedure for cytological specimens and is intended for the the staining of exfoliative cells in cytological specimens.