Interestingly, the young Atkins assumed one could only perform such complex fingerpicking with the thumb and, at minimum, two fingers, so that’s how he went about learning the style, never knowing that Travis pulled off his spectacular finger-plucked riffs with only his thumb and index finger.
Over the years, Atkins developed his own two- and three-finger rolls, as demonstrated in the example below (which channels the Travis’ composition “Walkin’ the Strings”). Here, the right hand simply alternates between thumb and index plucks throughout.
Throughout the phrase, the fretting hand forms a series of ascending chords in the general key of F major on the sixth, fourth, and third strings, with every fourth note being an open D. To get that authentic Atkins plucked sound, make sure to use a thumbpick on the low notes, and, for a slightly muted tone, lightly rest your plucking-hand palm on the third and fourth strings at the bridge.
Nailing Atkins’ overall tone isn’t as simple, if only because Mr. Guitar played so many guitars over the course of his career. He worked with Gretsch and later Gibson to create a line of instruments, including Gretsch’s famous 6120 (a favorite of Brian Setzer), Tennessean, and Country Gentleman models. Like his friend Les Paul, Atkins had a real knack for electronics and even came up with a stereo guitar setup with the bass and treble strings getting their own half-pickup so he could decide to run, say, only the bass strings through an echo unit (his effect of choice). It’s interesting that someone so accomplished would one time say, “Everything I’ve ever done was out of fear of being mediocre.”
(Special thanks to Jim Nichols, who was consulted in the writing of this piece.)