The way I understand imprinting, the first living thing a newly hatched chick sees it automatically assumes is mama. Since that first thing is usually the duck that is sitting on it this usually works fine. May I assume that you are intending to return this duckling to the wild? If so then maybe the best thing is probably to find some kind of wildlife organization nearby that can hatch and raise it, as they have all the training and equipment to do this properly. I'm not sure how receptive ducks are to orphans, especially if they themselves are not sitting at the time.
If you intend to do this yourself the most important thing is to make sure it only sees things that looks like a duck. Otherwise it can take to thinking that humans are all good and kind providers of protection and vittles. Feeding it using a duck-like puppet while you are shielded from view is one way to avoid human contact.
If you plan on keeping it as a pet or releasing it to the local public park than it really doesn't matter if it imprints on you or not. In my experience with ducks (domestic breeds) is that imprinting tends to fade as the bird matures and is less dependent on mommy for food and protection and is ready to start finding a mate of his/her own.
