ISO 4628-4:2016 specifies a method for assessing the degree of cracking of coatings by comparison with pictorial standards. ISO 4628‑1 defines the system used for designating the quantity and size of defects and the intensity of changes in appearance of coatings and outlines the general principles of the system. This system is intended to be used, in particular, for defects caused by ageing and weathering, and for uniform changes such as colour changes, for example yellowing.