Retinol dehydrogenase with a clear preference for NADP. Oxidizes all-trans-retinol, but seems to reduce all-trans-retinal with much higher efficiency (PubMed:18039331). Has no activity toward steroids (PubMed:18039331). . This is the function of RDH13 (retinol dehydrogenase 13, Ensembl gene identifier ENSG00000160439).