I've noticed that when i color my mmf it causes it to break down and become chalky especially colors that require a large amount like brown and black. Those are barely usable. I've tried wilton and americolor and they both cause my fondant to break down. Is there another brand that doesn't do this or something i can do differently? Thanks!!

When are you adding the color? Some people add some color to the marshmallows, before adding the other ingredients.

http://sugarsweetcakesandtreats.blogspot.com/2010/09/recipe-marshmallow-fondant-mmf.html

Hollyberry91, whenyou are making dark colors like black or red or even the lighter colors, it is always best to use powder food coloring (sold at your specialty cake shop or on line). You would need to disolve these in your liquids before adding the PS.
Americolor and Wilton both work great as well if the previous method is used.
When I make a batch of white fondant and need several different colors I always go with the lighter shade of food coloring and then either use my airbrush to intensify the color or dusting powders light luster and petal dust.

when you are adding in color, you need to add additional powdered sugar and shortening. The shortening will bring it back to a stretchy state and the sugar keeps it from being too soft.

Please help! I have had a perfectly awful day. I was making a chai tea cake with chai spice buttercream. The cake was to be a police shirt, dark navy blue. The fondant emblems, badge, crime scene tape, name badge, and handcuffs were made and looked really good. The cake came out perfectly, and tasted great. Then, the problems started. The buttercream (indydebi's) was a little stiff, so I added more milk. Still, it crusted so fast, I didn't have time to smooth it. Using a wet scraper or a hot scraper didn't help. The fondant (MMF) cracked, pulled apart, and refused to be smoothed at the corners, just pleated. I have used both these recipes before and had no problems, so it must be the additives. Should I have put lots more milk in the buttercream, or ....? How do you get dark colors without breaking down the fondant? I would appreciate some advice before I try something like that again or go out and buy a lot of different ingredients. Thanks for your help.