Coated paper has improved smoothness, hardness, whiteness and gloss and thus improves printing characteristics. Different sorts of starch depend on degree of purity and whiteness. The whiteness or darkness of clouds is a function of their depth. The colour difference arises mainly from the whiteness of myelin. Amiri Baraka argues that there is a "white jazz" genre that expresses whiteness. The whiteness of the face represent the whiteness and beauty of the spirit world. Class and education have an influence on the perceived whiteness of an individual. He considered this analysis applicable to many different qualities such as hotness, whiteness, and sweetness. Both parents need to have the allele for whiteness to have white cubs. Even the whiteness of the "toga virilis" was subject to class distinction. Several commentators have observed that "many American Jews retain an ambivalence about whiteness". Heishin was designed to be "heavy" on black to contrast with the "whiteness" of Enishi. Yet Kolchin describes a "persistent sense of unease " with certain aspects of whiteness studies. Black-body radiators are the reference by which the whiteness of light sources is judged. It is a Latinicized term meaning "whiteness".