Toss 'em outside in the sun and they'll be fixed in an hour. A day or two under indoor lights. If you're not sure, cover up a chunk and the difference will be clear. Some of the grays are noticeably yucky with the ambering.

I think it depends on the amount of sunlight. I recall that the sections of flooring that had direct sunlight changed color quickly (in a day or three). Other sections might have taken a week or so.

The guy where we're getting ours gave us the same warning because he had just brought us a new sample of one color and the rest had all been out on the floor. I asked how many years that took and he just started laughing...apparently it's a matter of hours for many colors.

I did half the kitchen on Friday, the other half on Saturday. By Sunday the first half had changed color, and by Monday the entire floor looked the same. I used Barbados (off white) and the dark grey/black planks.

I think they warn you so you expect it (which I appreciate!), but it's not a big deal at all. By the way, I have smaller, old house windows with no low-e coatings, so perhaps that helped with the ambering effect.

Ok... thanks so much! I will expect our samples to change soon enough then. I was concerned it might take longer. The look pretty darn yellow as they came out of the package yesterday. You'd think they would put them under lights before shipping as this is a first impression people are getting.
I really hope they turn out nice as I'd hate to have to start down yet another path....

(don't they smell nice?)