Posted by: Kate
I put my white swatches in a bright, south-facing window for the past week. Here's a before and after:
Real world application: back when I used to do portrait commissions, I would sometimes tell people that if their painting started to look a bit dark or dingy, to put it in the window for a few days to brighten it up again. I did hear back from some of my clients that they felt it made a noticeable difference to do this from time to time.