Georges Cera, was sure that color is easy to control, which we see in his works. On the canvas called "Rainbow", a rather interesting method was used. Sulfur made one device that resembled a circle, on it the artist applied all 7 colors of the rainbow, which were interconnected in halftones, in between the primary colors.
For example, between red and yellow, red-yellow was applied. There was a special rim on this ring, which should be white, so this light was mixed with all the other colors of the circle, and as a result, the artist obtained a full gamut of all colors and shades that he successfully used. Thanks to this device, this picture turned out, with the maximum use of all halftones.
On the canvas, you can see how the master was able to expose all the colors to patterns, so that the picture turned out to be surprisingly lively and natural, so the color interaction turned out most successfully.
On the canvas itself, you can see three children sitting on the banks of the river, most likely they were going fishing, although gear is not visible. In the distance you can see the roofs of houses and the tops of trees, and a rainbow spreads over them, delighting with its overflow of flowers, but the boys on the shore have nothing to do with it, they are doing something completely different.
Due to the fact that the artist was able to create a fairly convenient system to achieve a particular color, he uses his skill as best as possible, and during constant lighting, the color effects in the picture will sparkle in new colors.
Water on the canvas surprisingly accurately reflects the sky and even in the distance the visible tops of chapels, churches, temples. The strokes are very measured, so maximum realism is achieved.