Honestly girls, this is just due to staining of the porous free edge of the nail. Once it is trapped under an overlay, it is hard to flush that staining away and you know yourself women are right mucky creatures and do not clean under their enhancements with a nail brush often enough. :irked:
Tea, makeup, curry, and other more horrible things just stain the plate. 3 weeks between appointments is a long time to let your nails go uncleaned!! You will always notice that some are stained worse than others ... the using fingers naturally ... and some women (the more conscientious ones) don't have the same problem.
xx