Rainbow rose for this colouring process are "Rosa" La Belle and "Rosa" Avalanche+. However, these cultivars' rainbows are not as bright as "Vendela". Some vendors use the cultivar name to describe their products, "e.g.", Vendela Rainbow Rose, or Rose Avalanche Crystal Green. The Original Rainbow Rose has the seven colours of the rainbow and is the most popular rose in this category. However, there are also the tropical variant with combinations of red/pink and yellow, and the ocean variant with combinations of green and blue. Other colour combinations are also possible, though black and white are impossible to make. Rainbow rose The
Rainbow explained the dependence of the strength of the colours of the rainbow on the size of the water droplets. Modern physical descriptions of the rainbow are based on Mie scattering, work published by Gustav Mie in 1908. Advances in computational methods and optical theory continue to lead to a fuller understanding of rainbows. For example, Nussenzveig provides a modern overview. Experiments on the rainbow phenomenon using artificial raindrops, i.e. water-filled spherical flasks, go back at least to Theodoric of Freiberg in the 14th century. Later, also Descartes studied the phenomenon using a Florence flask. A flask experiment known as Florence's