The great San Kenton called his big band "THE COLORS IN SOUND to hint at the various sound textures he used (blending the instruments tones. A lyrical melody is enhanced (or colored) with another instrument doubling the line.
Stan Kenton did it using different instruments (for example: french horn and saxophone or). In this episode, Lou has two guitars with different tone qualities playing the melody, like a "doubling" effect. It can be like a burst of colorful tone.
Enjoy!