Look at this picture:
It is part of an Adobe Illustrator tutorial.
The tutorial is about using patterns, but what I am interested in is how to draw the darker parts inside the objects. I'am talking about, the darker green at the bottom of the green leaves.
If I were using a color, I would simply trace the path with the Pen Tool, and then apply a darker color. [Please tell me if there's a better way to do that.]
But here, given the patterns applied to the picture, I don't know how to proceed. Maybe there is some kind of transparency option in Illustrator? If yes, why is not an alpha channel added to the colors? In other words why is #rrggbb instead of #aarrggbb? The alpha option would have already been found by me in that case.