I need to do an outline of a t-shirt and fill it in, I was wondering if it could be done with Royal icing or if I have to use color flow? I've never used either before, and it's not till next Sunday that I need it, which is my next question. How far in advance can I make the decorations using royal or color flow?

Thanks!

Yes, you can. Just thin down your RI until it is the right consistency. You can make them weeks in advance, if you have someplace to store them out of humidity and where they won't end up broken.

thank you so much! I'm going to work on it today then, and make a couple of extra for just in cases's!

I think the only difference between royal and color flow (besides the color flow powder) is that a color flow piece has maybe a bit more "shine" to it when dried. I have dried color flow pieces, covered and out of of the light, that I don't plan to use for months. No worries.