When I started doing plein air painting, I used a more simplified palette. But then I noticed that the colors were more muted than my studio work. So now I take all my regular colors with me whether I paint indoors or outdoors. Sometimes the brights feel a bit exaggerated, but I really do try to determine what colors I see there outside (warm vs cool, and compare the tones). I like to put colors in the shadows and not just have brown muted tones like I had done in the past.
This was painted in the studio with my new color palette, and was based on an older plein air study I had done a few year's back. I am enjoying the more dramatic colors.