Contents of the paintings Styles changed frequently due to the extreme competitiveness of the artists at this time who all aspired to be the most creative with their prints. Originally, prints only consisted of black and white ink, but the invention of block printing allowed the quick production of identical prints with multiple colors. The addition of color in the ukiyo-e prints let artists further express their art through realism. At this time different kinds of artists started collaborating with each other to add different dimensions to their prints. Ukiyo-e artists mostly enjoyed painting everyday activities that were done outside. Artists especially paid close attention to contemporary affairs and fashions. Later, ukiyo-e painters began to enjoy painting indoor activities in which immediately grew popular in demand. The indoor activities that they liked to paint were usually parties in the Yoshiwara quarter of Edo. During the Kanbun era, actresses and courtesans briefly began to be seen in individual portraits until artists Utagawa Hiroshige and Katsushika Hokusai brought back the popularity of landscapes again through their prints.