Lightfastness -- comparing full strength paint
(bottom half is sun exposed strip)
Lightfastness -- comparing tints
(top half is the sun exposed strip)
Two weeks ago, I began testing these Mission Gold watercolors. (See the original post here.) After painting the test strips, I cut the page in half and put one piece in my flat files and the other in a spot that would get direct sun. Following my plan to compare the sheets every two weeks, I put the two pieces together today, first comparing the full-strength strips and then the lighter washes.
It's worth noting that the sun-exposed strip has had only a few hours of sun a day on the best days and we had 4 or 5 days of deeply overcast weather in the past two weeks. I'll continue to monitor the test strips and will post again when there is more information.