Retinol dehydrogenase with a clear preference for NADP. Converts all-trans-retinol to all-trans-retinal. Has no detectable activity towards 11-cis-retinol, 9-cis-retinol and 13-cis-retinol (By similarity). Required for normal embryonic development. all-trans-retinol + NADP(+) = all-trans-retinal + H(+) + NADPH Cofactor metabolism; retinol metabolism. Detected in retinal pigment epithelium (at protein level). First detected in the neural groove at 8.0 dpc. At 8.5 dpc, detected in lateral plate mesoderm, the dorsal region of the somites, the floor plate of the neural tube and in head mesenchyme. At 9.5 dpc, detected in dorsal paraxial mesoderm, lateral plate mesoderm and in nephrogenic cord tissues. At 10.5 dpc, detected in lung buds, developing mesonephros, mesodermal tissue surrounding dorsal root ganglia and adjacent to the forlimb buds. Belongs to the short-chain dehydrogenases/reductases (SDR) family.