Кумаров Ельдар

A school or classroom board - an integral attribute of a modern school - appeared in educational institutions at the beginning of the 19th century. Instead of personally approaching each student, teachers could now explain the subject immediately to the whole class, clearly showing information on a large board. Such boards were made of shale or wood, which was then covered with black paint. The latter option, due to its cheapness, has become more widespread.

Later, the developing industry was able to offer schools boards made of plastic and metal. The latter became widespread due to their magnetic properties, which turned out to be extremely convenient in everyday use. Initially, such boards were covered with matte black paint - no one thought about changing color to another. It was assumed that white traces of chalk would be clearly visible on a black background.

However, science does not stand still - by the middle of the 20th century, experts determined that when working with images for a long time, green color is the most optimal for the eyes. School teachers who received a trial batch of boards with a dark green coating confirmed that this color is much better at work, especially on bright sunny days, while in the light of the sun black boards with white inscriptions create a too contrasting image.

In the 1960s, green classrooms flooded first US schools and then western Europe. Much later, cool green boards came to the countries of eastern Europe, and nowadays it is rare to find a black chalk board.