A personalizable security document comprising: a substrate having a first side and a second side opposite to the first side in a thickness direction (d) of the substrate; and a security feature (3a; 3b) formed in the substrate and extending through at least part of the substrate along the thickness direction (d), wherein the security feature (3a; 3b) includes: a first layer including a laser-engravable portion configured to have an image laser engraved in the same, the laser engraved image being visible when the substrate is viewed from the first side under white light; a second layer arranged below the first layer, the second layer including a first pattern overlapping at least in part the laser-engravable portion when viewed along the thickness direction, the first pattern being visible at least in part when the substrate is viewed from the second side under UV light; characterised in further comprising: a third layer arranged below the second layer, the third layer including a second pattern overlapping at least in part the laser-engravable portion when viewed along the thickness direction, wherein each of the first pattern and the second pattern is visible at least in part when the substrate is viewed from the second side under UV light, the first pattern and the second pattern emitting light of a first color and a second color, respectively, upon irradiation with the UV light. a substrate having a first side and a second side opposite to the first side in a thickness direction (d) of the substrate; and a security feature (3a; 3b) formed in the substrate and extending through at least part of the substrate along the thickness direction (d), wherein the security feature (3a; 3b) includes: a first layer including a laser-engravable portion configured to have an image laser engraved in the same, the laser engraved image being visible when the substrate is viewed from the first side under white light; a second layer arranged below the first layer, the second layer including a first pattern overlapping at least in part the laser-engravable portion when viewed along the thickness direction, the first pattern being visible at least in part when the substrate is viewed from the second side under UV light; characterised in further comprising: a third layer arranged below the second layer, the third layer including a second pattern overlapping at least in part the laser-engravable portion when viewed along the thickness direction, wherein each of the first pattern and the second pattern is visible at least in part when the substrate is viewed from the second side under UV light, the first pattern and the second pattern emitting light of a first color and a second color, respectively, upon irradiation with the UV light. a first layer including a laser-engravable portion configured to have an image laser engraved in the same, the laser engraved image being visible when the substrate is viewed from the first side under white light; a second layer arranged below the first layer, the second layer including a first pattern overlapping at least in part the laser-engravable portion when viewed along the thickness direction, the first pattern being visible at least in part when the substrate is viewed from the second side under UV light; characterised in further comprising: a third layer arranged below the second layer, the third layer including a second pattern overlapping at least in part the laser-engravable portion when viewed along the thickness direction, wherein each of the first pattern and the second pattern is visible at least in part when the substrate is viewed from the second side under UV light, the first pattern and the second pattern emitting light of a first color and a second color, respectively, upon irradiation with the UV light.