I like them both....but i think your application may make it sway one way or the other. For instance, i would pick the black backround if the scan is going to be on a webpage with other black items. On my website, I used a black backround for my sidebar which has all the page links. So to match that and the print color, I used black backround for the chips on my trader page. Originally I had white backrounds, but i think the black is nicer.

So...hope this helps. Personally...I like the black.