I am following so many blogs (and believe me, I did not update the list on the right in last half a year, at least), that I am catching up techniques and tips, and then cannot even tell, where the idea came from. It is the case with the trick I used on almost all my weekend photos, taken midday, on beautiful, sunny, no-cloud-in-the-sky day. I usually carry a graduated filter in my photo bag, and this is where it usually stays. I tend to use polarizer, but I will put it in before going out to shoot. Anyway, I had all those pictures with no detail in the sky, and no color either. But as the sky was just blue, I simply added a graduated filter in Lightroom, adding some blue color to it in a process.