I scraped my painting of Balboa Island Mini Mart from last Friday. My perennial problem is that I am not getting the relative values correctly (comp wasn't great either--earlier arrivers had prime spots taken already). I was painting under both an umbrella and with a very wide-brimmed SPF-40 hat. Still, my pupils must have been cranked down so hard that when I look at the painting later at home, the values and colors are wa-a-y off. I'm not sure what to do. Got suggestions?