Color theory primary colors work at all is that the imperfect pigments being used have sloped absorption curves, and thus change color with concentration. A pigment that is pure red at high concentrations can behave more like magenta at low concentrations. This allows it to make purples that would otherwise be impossible. Likewise, a blue that is ultramarine at high concentrations appears cyan at low concentrations, allowing it to be used to mix green. Chromium red pigments can appear orange, and then yellow, as the concentration is reduced. It is even possible to mix very low concentrations of the blue mentioned and
Paired metamorphic belts barometric conditions within these 2 regions are recorded and preserved through distinct types of metamorphism and mineral assemblages. Detailed research on constraints of metamorphic mineral stability fields allows accurate inference of previous regional thermal and barometric conditions. Metamorphic belts are a consequence of thermal perturbations, due to low temperature with respect to pressure ratios (dT/dP) in oceanic trenches and high temperature with respect to pressure ratios (dT/dP) in arcs. Paired metamorphic belts are the product of subducted colder crustal rocks, which are taken to depth, metamorphosed and then exhumed. However, if the rock unit is not exhumed relatively quickly after