Iowa Code § 43.27: Printing of ballots.

The text printed on ballots of each political party shall be in black ink, on separate sheets of paper, uniform in quality, texture, and size, with the name of the political party printed at the head of the ballots, which ballots shall be prepared by the commissioner in the same manner as for the general election, except as provided in this chapter. The commissioner may print the ballots for each political party using a different color for each party. If colored paper is used, all of the ballots for each separate party shall be uniform in color.