Searching for inspiration i stumbled over the old billboards from Teekanne. They are from the twenties and thirties and made by Jupp Wiertz and Heinrich Molge. Jupp Wiertz for example was on of the most important german representative of advertising art. He made billboards for Odol and Seifenflocken Lux just to name two of his works.
Unfortunately he also designed for the Nazis. He stayed by his own style instead of changing to the “trend of the time”. So these works of that time also are striking and have watercolor character. Jupp Wiertz died at the end of the thirties because of a sepsis. About Heinrich Molge i couldn´t find more information than he was a graphic designer and illustrator. Also the birthdate i found just shows the year 1888. The following billboards mostly are made by him.