ATPL: In order to perceive colour vision, it is necessary:-1: for there to be sufficient amount of light (ambient luminosity)-2: at night to look at the point to be observed at an angle of 15°-3: to allow the eye a period of time to get used to the light-4: to avoid white light

Explanation: In order to perceive colour vision, it is necessary:-1: for there to be sufficient amount of light (ambient luminosity)-2: at night to look at the point to be observed at an angle of 15°-3: to allow the eye a period of time to get used to the light-4: to avoid white light