I will be watching this thread close!!! After reading a few threads the last few days about purple turning blue and fading out I was getting scared. I also have a cake coming up with lavender tulips. I was hoping to do them way in advance.
It seems that lavendar and blue are very light sensitive, so at least keep them in the dark if you're still planning on doing ahead of time!
I may have mentioned this before in another thread but if you will make a batch of royal icing, color it whatever color you want, then add it to the bc, it will take the color more evenly and easily. It doesn't change the taste. I haven't had any problem with my violet turning blue except in the bag after it has been sitting out for several days. But used fresh and in royal icing decorations I've not seen any of the problems you mentioned.
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