Color Change of Exotics - Help Needed

[Johan]

Can anyone tell me where I would find out which elements in nature
change the color of some exotic species of wood? I know that the sun
plays a major role, it will change a dull piece of Kurupay into the
most beautiful wine red piece of wood in a matter of a few hours.
Which rays of the sun does that and what else is needed, if any, for
the dramatic change to take place?

I am looking for a way to do this artificially, but need to know where
to start. I am hoping that this is also possible using chemicals.

Help will be very much appreciated
Thanks
Johan

[Thanks to D.Staples for your input. I have done a lot of digging, but
have not found anything yet. I will keep looking.]