Photosynthesis was measured with CO2/H2O gas analyzer on intact leaves of rose ‘Akito’ at narrow band light of 18 wavelengths. Subsequently, the optical properties (transmittance, absorptance and reflectance) were measured with spectrophotometer. A mechanistic crop model was used for up scaling measurements at the single leaf level to the crop level (crop with LAI = 3). The green and the reddish leaves had similar total PAR absorptance, even though absorptance around 550nm was slightly lower in the green leaves. The maxima of photosynthesis efficiency were at 640–680nm for quantum yield (per absorbed light unit) and at 660–680nm for action spectrum (perincident light unit), regardless the colour of the leaf blade. In the range 500–580 nm, both the quantum yield and the action spectrum were lower in reddish than in green leaves. Differences in optical properties and photosynthetic behaviour were related to the higher content of anthocyanins in red leaves.