Okay...we all know that purple is the most heinous of colors because of its tendency to fade and change colors. The best way to get around this is to dust whatever it is that you want to stay purple.
These hydrangeas started out lavender. I dusted them first with a lighter purple/lavender color.
Then you dust the center with a little darker purple. For these I used French Lilac and Grape Crystal Colors dusts.
Make sure that when you dust the flowers you don't extend the color all the way to the edge of the petal, and that you keep the darker color mostly in the center. But a little variation is good because no two flowers are the same anyway.
Use a big, rounded, fluffy mop brush like a puffy powder makeup brush to make sure that the color isn't too concentrated in one area.
Here's the before and after of the non-dusted and dusted versions. By layering the color the purple looks more natural, and since it's petal dust it won't fade.
And you can pin the image on the right to see the whole process and save it for later. :)
Kara Buntin owns A Cake To Remember LLC in Richmond VA, and cake supplies online at www.acaketoremember.com and www.acaketoremember.etsy.com