A method of making a security device, comprising: (a) forming an array of focussing elements on a first region of a first surface of a focussing element support layer, by: (a)(i') applying a pedestal layer comprising at least one transparent material onto at least the first region of the first surface of the focussing element support layer; (a)(i) applying at least one transparent curable material either to the pedestal layer or to a casting tool carrying a surface relief corresponding to the focussing elements, over at least the first region; (a)(ii) forming the transparent curable material(s) with the casting tool by bringing the first surface of the focussing element support layer against the casting tool such that the at least one transparent curable material is between the surface relief and the pedestal layer, across at least the first region; and (a)(iii) curing the transparent curable material(s) on the pedestal layer so as to retain the surface relief in the first region; wherein the focal length of the focussing elements is such that their focal plane lies either substantially on the first surface of the focussing element support layer, or beyond the first surface of the focussing element support layer relative to the location of the array of focussing elements, and wherein: the at least one transparent material forming the pedestal layer is more flexible than the at least one transparent curable material applied in step (a)(i) once fully cured; and/or the at least one transparent material forming the pedestal layer comprises at least two transparent materials (207a, 207b) having different optical detection characteristics, the at least two transparent materials (207a, 207b) being applied to different respective laterally offset sub-regions (208a, 208b) of the focussing element support layer in the first region; and/or the pedestal layer has a first height in a first sub-region of the first region and a second different height in a second sub-region of the first region. (a) forming an array of focussing elements on a first region of a first surface of a focussing element support layer, by: (a)(i') applying a pedestal layer comprising at least one transparent material onto at least the first region of the first surface of the focussing element support layer; (a)(i) applying at least one transparent curable material either to the pedestal layer or to a casting tool carrying a surface relief corresponding to the focussing elements, over at least the first region; (a)(ii) forming the transparent curable material(s) with the casting tool by bringing the first surface of the focussing element support layer against the casting tool such that the at least one transparent curable material is between the surface relief and the pedestal layer, across at least the first region; and (a)(iii) curing the transparent curable material(s) on the pedestal layer so as to retain the surface relief in the first region; wherein the focal length of the focussing elements is such that their focal plane lies either substantially on the first surface of the focussing element support layer, or beyond the first surface of the focussing element support layer relative to the location of the array of focussing elements, and wherein: the at least one transparent material forming the pedestal layer is more flexible than the at least one transparent curable material applied in step (a)(i) once fully cured; and/or the at least one transparent material forming the pedestal layer comprises at least two transparent materials (207a, 207b) having different optical detection characteristics, the at least two transparent materials (207a, 207b) being applied to different respective laterally offset sub-regions (208a, 208b) of the focussing element support layer in the first region; and/or the pedestal layer has a first height in a first sub-region of the first region and a second different height in a second sub-region of the first region. (a)(i') applying a pedestal layer comprising at least one transparent material onto at least the first region of the first surface of the focussing element support layer; (a)(i) applying at least one transparent curable material either to the pedestal layer or to a casting tool carrying a surface relief corresponding to the focussing elements, over at least the first region; (a)(ii) forming the transparent curable material(s) with the casting tool by bringing the first surface of the focussing element support layer against the casting tool such that the at least one transparent curable material is between the surface relief and the pedestal layer, across at least the first region; and (a)(iii) curing the transparent curable material(s) on the pedestal layer so as to retain the surface relief in the first region; the at least one transparent material forming the pedestal layer is more flexible than the at least one transparent curable material applied in step (a)(i) once fully cured; and/or the at least one transparent material forming the pedestal layer comprises at least two transparent materials (207a, 207b) having different optical detection characteristics, the at least two transparent materials (207a, 207b) being applied to different respective laterally offset sub-regions (208a, 208b) of the focussing element support layer in the first region; and/or the pedestal layer has a first height in a first sub-region of the first region and a second different height in a second sub-region of the first region.