What determines the width and brightness of the rainbow?

According to calculations according to the formulas of the diffraction theory, which were performed for drops of different sizes, the width of the rainbow, its presence, the location and brightness of colors, as well as the position of the arcs themselves, depend directly on the size of the rain drops. So, for drops with a radius of 0.5 to 1 mm, the outer layer of the main rainbow will be a bright dark red color, followed by a light red color and all other shades of the rainbow. Violet and green colors will appear especially bright in this case. With a 0.25mm radius of raindrops, the red edge of the rainbow will appear less intense. The rest of the colors will have the same intensity, but some purple arcs will be replaced by green. With a radius of raindrops of 0.1 and 0.15 mm, there will be no red color in the rainbow. The outer layer of the rainbow will be orange, and the additional arcs will be more and more yellow. And between them and the main rainbow and the first additional rainbow, characteristic gaps will appear. Thus, it turns out that it is by the color of the rainbow that you can determine the size of the raindrops. The larger the raindrops, the brighter the rainbow will be.