Place popcorn in a large roasting pan; keep warm in a 250 degree oven.

Meanwhile, in a large heavy saucepan, combine the sugars, water, corn syrup, vinegar and salt.

Cook and stir over medium heat until mixture comes to a boil.

Cook, stirring occasionally, until a candy thermometer reads 250 degrees (hard ball stage).

Remove from the heat; stir in butter until melted. Stir in food coloring. Drizzle over warm popcorn and toss to coat. Cool.

Break into pieces. Store in an airtight container.