At the turn of the century artists did not have art stores like Dick Blick and Hobby Lobby. They definitely couldn’t access the internet. When the chips were down and they could not afford or find the materials they were looking for they improvised.
This was a single layer of cardboard similar to to what Victorian Era painters would find and add a substance called Gesso or enamel paint to it. Typically the artist of that era would use oil paints, because acrylic paint had not been invented yet. The process of creating this board would be improved over the years and become known as illustration board. This is single layer cardboard, but has a thin sheet of paper bonded to it.
On this piece of Gessoed cardboard I experimented with watercolor. I am not the one who invented this technique. It keeps the watercolor liquid longer, because it does not bond with the paper as quickly. It is delicate and movable much like gouache or wet oil paint. It does create murky blobby affects and does not allow the watercolor to bond as precisely as on watercolor paper, but it does maintain the appearance of texture. The texture is like faux painting, you can manipulate it before you even start with painting content.
As enjoyable as this experiment is, I believe mastery could take some time and skill and forethought. If you have some single layer cardboard laying around and some gesso, give it a shot, maybe you’ll like it.