One day before ballots are due, Portland City Elections Officer Deborah Scroggin fined Mayor Ted Wheeler $500 for violating disclosure rules on a recent campaign mailer for the May primary.

His violation? The font disclosing his donors was too small.

"The required disclosure was in a font clearly smaller than all other font on the communication and difficult to read to a person with average reading abilities," Scroggin wrote in a May 18 letter to Wheeler's campaign. "As a result, the disclosure is not prominent and therefore constitutes a violation of City Campaign Regulations. The financial penalty considers the overall budget and resources available to the campaign, the number of previous violations within this elections cycle, and the size of the intended audience of the mailer in question."

Scroggin, who has had a busy couple of months fielding complaints about new campaign finance limits and disclosure requirements voters approved in 2018, also issued letters of warning to two other candidates: Ozzie González, who is challenging Wheeler, and Keith Wilson, who is challenging Commissioner Chloe Eudaly.

She dinged González for a lack of disclosure about his contributors on his website, videos and social media accounts.

Wheeler's campaign manager, Amy Rathfelder, says she thinks the mayor's campaign mailer satisfied legal requirements.

"In our design, we ensured that the disclaimer was clear and legible, and we believe it is sufficiently prominent," Rathfelder says, adding that the campaign will nonetheless pay the fine.

Ballots must be delivered to official drop-off spots by 8 pm May 19 in order to be counted.