I was asked to take photos for a school dance. I have a Canon Speedlite 430EXII and an umbrella. The background was a sky blue with clouds and they had a lit up tower next to the people. They had stage lighting above me which they turned down some but there were multi-colored stage lights out in front of the stage that were lighting up the area also. My photos turned out grainy looking. I had set my umbrella up at home and practiced several times and all images came out great. Is it the lighting situation that caused this? Is there anything I can do to help the photos? I have used a cool down effect in editing to help them but it doesn't fix the issue completely. Thanks for all of your knowledge!!! Just wanting to learn.