If you search CIE colour Home › Forums › General Discussion › New street lights fitted !! › If you search CIE colour 1 August 2018 at 8:28 am #579794 Nick WhiteParticipant If you search CIE colour space you’ll find all the maths for doing the calc. Wiki has a good page on the subject (could have saved my thumbs by pointing you there in the first place!).