Shortly after the switch to United Artists, the series became even more popular. Walt Disney had seen some of Dr. Herbert Kalmus' tests for a new three-strip, full-color Technicolor process, which would replace the previous two-tone Technicolor process. Disney signed a contract with Technicolor which gave the Disney studio exclusive rights to the new three-strip process through the end of 1935, and had a 60% complete "Symphony", "Flowers and Trees", scrapped and redone in full color. "Flowers and Trees" was the first animated film to use the three-strip Technicolor process, and was a phenomenal success. Within a year, the now-in-Technicolor "Silly Symphonies" series had popularity and success that matched (and later surpassed) that of the "Mickey Mouse" cartoons. The contract Disney had with Technicolor would also later be extended another five years as well.