Kant and the Categorical Imperative

Here is an ethical dilemma for us to think through the Kantian lens:

In 1999, the dean of the Harvard Divinity School was fired from his university position because his office computer was found to contain pornography featuring sex between consenting adults. Otherwise, the dean's behavior was exemplary, and his job performance was considered by Harvard to be of the highest caliber.

• Which kinds of 'duties' are at play here, perfect or imperfect?