A security device for verifying an authenticity of a security document, in particular of a banknote, a passport, a document of value, a certificate, or a credit card, the security device comprising - an at least partially transparent substrate with a first surface and a second surface, wherein the substrate comprises at least a first substrate layer and a second substrate layer, - a first pattern arranged on the first surface of the substrate, wherein the first pattern is derivable using a first seed pattern, - a second pattern arranged on the second surface of the substrate, wherein the second pattern is derivable using a second seed pattern, - a third pattern arranged between the first substrate layer and the second substrate layer, which third pattern is derivable using the first pattern, the second pattern, and a third seed pattern, wherein for each corresponding quadruple of pixels comprising a pixel of the first pattern with a pixel value d1, a pixel of the second pattern with a pixel value d2, a pixel of the third pattern with a pixel value d3, and a pixel of the third seed pattern with a pixel value b, the third pattern is derived such that d 3 = 1 − 1 − b 1 − d 1 1 − d 2 wherein transmittances and reflectivities of the first pattern, of the second pattern, of the third pattern, and of the substrate are selected such * that in a transmission viewing mode, for at least one transmitted wavelength through the first pattern, through the second pattern, through the third pattern, and through the substrate, the third seed pattern is visible, * that in a first reflection viewing mode, for at least one reflected wavelength from the first pattern and/ from the first surface, the first seed pattern is visible, and * that in a second reflection viewing mode, for at least one reflected wavelength from the second pattern and/ from the second surface, the second seed pattern is visible, wherein a first histogram of the first pattern comprises at least a first unpopulated region (H10u) and at least a first populated region (H10p), and wherein a second histogram of the second pattern comprises at least a second unpopulated region (H20u) and at least a second populated region (H20p), and wherein the first unpopulated region (H10u) at least partially overlaps the second unpopulated region (H20u) and wherein the first populated region (H10p) at least partially overlaps the second populated region (H20p). - an at least partially transparent substrate with a first surface and a second surface, wherein the substrate comprises at least a first substrate layer and a second substrate layer, - a first pattern arranged on the first surface of the substrate, wherein the first pattern is derivable using a first seed pattern, - a second pattern arranged on the second surface of the substrate, wherein the second pattern is derivable using a second seed pattern, - a third pattern arranged between the first substrate layer and the second substrate layer, which third pattern is derivable using the first pattern, the second pattern, and a third seed pattern, * that in a transmission viewing mode, for at least one transmitted wavelength through the first pattern, through the second pattern, through the third pattern, and through the substrate, the third seed pattern is visible, * that in a first reflection viewing mode, for at least one reflected wavelength from the first pattern and/ from the first surface, the first seed pattern is visible, and * that in a second reflection viewing mode, for at least one reflected wavelength from the second pattern and/ from the second surface, the second seed pattern is visible,