surface area

space height ratio

illumination

coefficient of utilisation

object should be viewed from a distance

object should be move constantly

object should be viewed from a close vicinity

viewer should move constantly

ageing of the lamps

type of work carried out at the premises

lamp cleaning schedule

all of the above

size of the room

space height ratio of the lamps

colour of walls/ceiling

all of the above

increasing the mounting height of the lamp

using diffusers

using reflectors to cut-off the light at certain angle

all of the above