While a reasonable amount of literature has been generated in this area, there has been no consistency in artificial weathering conditions so it is difficult to compare and contrast historical findings. Descriptions of the weathering process are often scant or, in some instances, completely absent. So while these studies convincingly demonstrate detrimental effects that can be induced by sunlight, a good sense of the magnitude of this damage, in relation to better-understood hair insults (e.g. chemical treatments, heat, etc.), is yet to be determined.