Techniques for manufacturing a light field print using a printing press. The techniques include: identifying at least one characteristic of the printing press at least in part by printing at least one calibration pattern; obtaining content to be rendered using the light field print, the content comprising multiple scene views; generating, based at least in part on the content and the at least one characteristic of the printing press, a front target pattern and a back target pattern; and using the printing press to: print the front target pattern on a first side of a substrate; and print the back target pattern on a second side of the substrate.

A visual security feature is provided that is disposed on a target. The visual security feature includes two substantially transparent layers. At least one of the two substantially transparent layers is present in an image-wise pattern.

A visual security feature is provided that is disposed on a target. The visual security feature includes two substantially transparent layers. At least one of the two substantially transparent layers is present in an image-wise pattern.

A substrate is printed with front side and back side markings in a first color ink. The front side when viewed with reflected light includes a first marking printed in a first saturation and a first symbol printed in the first saturation. The back side when viewed with reflected light includes: a second marking printed in a second saturation; a second symbol printed in the second saturation; a third marking printed in the first saturation; and a third symbol printed in the first saturation. The first marking, the second marking, and the third marking are printed to provide an interlocking pattern of low saturation color and high saturation color when viewed with transmitted light. The second symbol is visible, and the first symbol and the second symbol are not distinguishably visible, when viewed with transmitted light.

A substrate is printed with front side and back side markings in a first color ink. The front side when viewed with reflected light includes a first marking printed in a first saturation and a first symbol printed in the first saturation. The back side when viewed with reflected light includes: a second marking printed in a second saturation; a second symbol printed in the second saturation; a third marking printed in the first saturation; and a third symbol printed in the first saturation. The first marking, the second marking, and the third marking are printed to provide an interlocking pattern of low saturation color and high saturation color when viewed with transmitted light. The second symbol is visible, and the first symbol and the second symbol are not distinguishably visible, when viewed with transmitted light.

A method for forming an optical device and an optical device, wherein upon illumination, exhibits diffractive images dependent upon viewing angle, the device having a diffractive structure including grating regions, each region corresponding to a component of a respective diffractive image, wherein: each region of the diffractive structure includes grating elements along a first direction having a principal orientation component within the device plane that is substantially orthogonal to the first direction; wherein, the grating elements within each grating region have a constant pitch and the same orientation wherein each grating region, upon illumination, exhibits a diffractive color wherein the corresponding diffractive image is exhibited; wherein, the diffractive structure includes first and second grating regions elongated along a common first direction, the regions being adjacent along the first direction, and wherein the pitch and/or orientation of the grating elements of the first and second grating regions are different.

A method for forming an optical device and an optical device, wherein upon illumination, exhibits diffractive images dependent upon viewing angle, the device having a diffractive structure including grating regions, each region corresponding to a component of a respective diffractive image, wherein: each region of the diffractive structure includes grating elements along a first direction having a principal orientation component within the device plane that is substantially orthogonal to the first direction; wherein, the grating elements within each grating region have a constant pitch and the same orientation wherein each grating region, upon illumination, exhibits a diffractive color wherein the corresponding diffractive image is exhibited; wherein, the diffractive structure includes first and second grating regions elongated along a common first direction, the regions being adjacent along the first direction, and wherein the pitch and/or orientation of the grating elements of the first and second grating regions are different.

A security system, such as a banknote, comprises: i) a substrate, ii) a first ink, which is applied on at least a part of at least one surface of the substrate, wherein the first ink includes at least one IR luminescent dye and/or at least one IR luminescent pigment, and iii) a second non-luminescent ink, which is applied on at least a part of at least one surface of the substrate onto which the first ink is/are applied, wherein the second ink includes at least one non-luminescent IR absorbing pigment and/or a least one non-luminescent IR absorbing dye, wherein the first ink and the second ink at least partially overlap on the at least one surface of the substrate, wherein the second ink is applied in the overlapping area onto the first ink, and wherein the emission spectrum of the first ink and the absorption spectrum of the second ink at least partially overlap.

A security system, such as a banknote, comprises: i) a substrate, ii) a first ink, which is applied on at least a part of at least one surface of the substrate, wherein the first ink includes at least one IR luminescent dye and/or at least one IR luminescent pigment, and iii) a second non-luminescent ink, which is applied on at least a part of at least one surface of the substrate onto which the first ink is/are applied, wherein the second ink includes at least one non-luminescent IR absorbing pigment and/or a least one non-luminescent IR absorbing dye, wherein the first ink and the second ink at least partially overlap on the at least one surface of the substrate, wherein the second ink is applied in the overlapping area onto the first ink, and wherein the emission spectrum of the first ink and the absorption spectrum of the second ink at least partially overlap.

In some examples, a security element includes a substrate that, on one of its sides, includes at least one security feature extending over a first area, the security feature being configured in the form of a three-dimensional intaglio structure. A first ink group in the security feature includes a plurality of first raised image elements containing intaglio printing ink of the first color, and at least one second ink group in the security feature includes a plurality of raised image elements containing intaglio printing ink of a second color that differs from the first color, and these are provided and arranged offset and spaced apart from one another such that they form an optically variable structure and/or at least some of the mutually adjacent image elements, which differ from one another in the color, occlude and/or expose one another to varying degrees from a varying viewing angles.