Preheat oven to 450°F. Cut potatoes into 3x1/2-inch wedges. Place in large bowl. Add oil; toss to coat well.
Mix chili powder and salt. Sprinkle over potatoes; toss to coat evenly. Arrange potatoes in single layer on foil-lined 15x10x1-inch baking pan.
Bake 30 minutes or until potatoes are tender and golden brown. Mix ranch dressing and food color in medium bowl until well blended. Serve with potatoes for dipping.