collectively

Individually, a tiny speckle of roller-splashed emulsion is barely noticeable, but after three or four sweeps of the ceiling (increased from the initial expected one-and-a-bit when the first half-tin of paint turned out to be a different and noticeably greyer sort of white than the stuff it was supposed to be refreshing) the build-up of little speckles on a few bits of the floor (and a few of the children's toys and books) not covered by dust sheets required a fairly vigorous application of baby-wipe to get them back to normal.