A security document includes a first ink layer and a second ink layer. The first ink layer includes a first color in a first color zone and a second color in a second color zone offset from the first color zone in a first direction, and a first blended color including a mixture of the first and second colors in a first blended color zone between the first color zone and the second color zone. The second ink layer includes a third color in a third color zone and a fourth color in a fourth color zone offset from the third color zone in a second direction, and a second blended color including a mixture of the third and fourth colors in a second blended color zone between the third color zone and the fourth color zone. The first direction is different than the second direction.