I purchased the bourjois healthy mix serum foundation last summer online..off of ebay ( Only sold in Europe and Canada) so i picked out 52 as my shade as i watched a ton of videos and read blogs.. I still currently use it. but im almost out.. so the prblem is that when i put on 52 it comes out my skin color but once it oxidizes it turns like a half shade darker.. its not noticeable but it kinda bothers me.. and also when i put it on my hand it does look quite dark but not that dark where you notice it. so im going to purchase another one since im almost out.. should i purchase 51?.. it might look light but when it oxidizes it might look like my shade.. or go with my usual 52.? for reference im between a nc15/ nc20 51 or 52