Place your popcorn evenly on two large baking pans covered with parchment paper.
In 1 large saucepan over medium heat.
Add your butter first and melt.
Stir in sugar, corn syrup, vanilla, and salt into both saucepans.
Bring to boil while stirring.
Once at a boil allow to cook without stirring for four minutes.
Remove from heat.
Set to the side.
Split the mixture into 4 small mixing bowls or 4 small saucepans.
Add your food colors to the bowl, one color in each separate bowl.
Mix all bowls until the mixture is evenly colored and combined.
Stir in baking soda to each bowl.
Add your popcorn to each bowl about 2 cups of popped popcorn for each color.
Toss to combine to evenly coat.
Pour your popcorn on a baking sheet that you have covered with parchment paper.