Nuccios Nurseries maybe can provide you with information on Grape Soda (they either still sell it or used to).

look in the "gallery" portion of this forum. there is a post by that name with an image. the form of the flower is rather plain and small but it looks purple to me.

edj886: Grape Soda is indeed in purple color, especially at early stage to open. After the flower is fully open, it tends to have reddish purple color as the picture. Even it is a small and single flower, I like it very much due to the unique color.

I have a seedling from Grape Soda X Black Magic. However the seedling flower is deep red with slightly purple vein, little of purple. But I have many of the same cross, one of them might be in very dark color.

Here is a link that might be useful: {{gwi:503031}}