Abstract: A three-dimensional physical model for representing the set of colors reproducible in a given medium by combining three primary colors and a base color. The model consists of a plurality of discrete elements, each representing a distinct color reproducible by combining one or more of the primary colors and base color in a unique proportion. The discrete elements may be physically assembled to form a three-dimensional cuboidal model and disassembled to enable visualization of the interior elements of the model. The model enables development of an intuitive understanding of color theory and facilitates mapping of a selected color from one color medium (such as a computer color monitor) to another color medium (such as a photographic slide).

Abstract: An edger mill having a pair of edging rolls mounted for variable positioning apart from each other is powered by a plurality of electric motors driving the rolls from above, having a long shaft extending upwardly from each roll, with a bull wheel connected to each shaft in driving relation, each bull wheel having two or more electric motors connected thereto in driving relation by respective pinions. Synchronization between the edging rolls may be effected by mounting the bull gears in mutual intermeshing relation, or by using synchronous motors so that the common bus supply to the motors constitutes a synchronizing agency to maintain the edging rolls in synchronized relation.