Bob, but black. I've written about the dark blotches on the front of the house before. Looking at the photos I've taken over time, the transformation of the house from fresh pine to a dark grey is clear to see. On the front, however, it's not just a nice weathered grey but grey with black mottling.
Margaret wrote me recently they she thought the spots were getting worse. As I posted before, it seems the they're a type of mold or fungus. It's natural they grow only on the most exposed side of the house; moisture is necessary for mold growth.
When we go next week, I plan to use fungus treatment on the wood. Rutger and I bought a solution, as advised by the expert at Bauhaus, and Janne is lending me his power washer. At the moment, Sooz and I plan to brush on the fungus-killer, and then give it a good power rinsing. There's some thought about using bleach and/or soap, but I think I'll be conservative and try this stuff first. We plan to be back in mid-October, and we can be more aggressive then if needed.
I assume this will just kill the mold, not remove its effects altogether. That being the case, we'll still have to paint at least that exposure of the house next summer, if we can decide on a color!