It could've been either. I really remember bright clothing as well, though black may well have figured largely. She was very much in contrast with the more serious, black-clothed man opposite her, but I could be remembering her outfit wrong. Thank you for looking so diligently! (:
Well after a number of searches and looking through more kinky artwork than I care to admit, my search turned up nothing that matched your description.
This likely means one of two things: 1)The deviation was taken down for some reason, or 2)The artists didn't do their search tags right and as a result it doesn't turn up in any of the searches related to what it depicts.
There's also a third possibility, and that is that deviantart's search engine kind of sucks. I don't know if this is still true, but it has been pretty bad in the past. It seemed to be doing what it's supposed to though tonight. (That is, most popular/best quality deviations on top, and less popular deviations going down the page).
If this was a popular deviation when you saw it, my hunch is that it was taken down by the artist. This happens fairly often around here, sometimes it's due to art theft, other times controversy, or maybe the artist left dA altogether. I would check on google if you haven't already, because often times a popular image will be uploaded by someone else on another internet site with more obvious search tags. You may even find the artist him/herself who just moved to a different art site.