A method of forming an optical security device, comprising: providing a sacrificial arrangement of focusing elements disposed over an arrangement of image icon elements (18, 20); forming a pattern of a first contrasting material and a pattern of a second contrasting material on or in the image icon elements by directionally curing at a first cure angle, through the sacrificial arrangement of focusing elements, at least the first contrasting material on or in the image icon elements (18, 20), wherein the sacrificial arrangement of focusing elements has a first sacrificial lens pattern that is matched with the first contrasting material pattern at the first cure angle; wherein at least one synthetic image is a projection of both the first and second contrasting material patterns when viewed from at least one angle; and wherein the at least one synthetic image produces a color-transition effect which corresponds to a shift in viewing angle, the method further comprising: disposing a fixed arrangement of focusing elements over the arrangement of image icon elements such that the image icon elements (18, 20) project at least one synthetic image when viewed through the fixed arrangement of focusing elements; wherein the fixed arrangement of focusing elements has a first fixed lens pattern that forms a lens-icon pattern mismatched between the first fixed lens pattern and the patterns of the first and second contrasting materials (24, 32). providing a sacrificial arrangement of focusing elements disposed over an arrangement of image icon elements (18, 20); forming a pattern of a first contrasting material and a pattern of a second contrasting material on or in the image icon elements by directionally curing at a first cure angle, through the sacrificial arrangement of focusing elements, at least the first contrasting material on or in the image icon elements (18, 20), wherein the sacrificial arrangement of focusing elements has a first sacrificial lens pattern that is matched with the first contrasting material pattern at the first cure angle; wherein at least one synthetic image is a projection of both the first and second contrasting material patterns when viewed from at least one angle; and wherein the at least one synthetic image produces a color-transition effect which corresponds to a shift in viewing angle, the method further comprising: disposing a fixed arrangement of focusing elements over the arrangement of image icon elements such that the image icon elements (18, 20) project at least one synthetic image when viewed through the fixed arrangement of focusing elements; wherein the fixed arrangement of focusing elements has a first fixed lens pattern that forms a lens-icon pattern mismatched between the first fixed lens pattern and the patterns of the first and second contrasting materials (24, 32). disposing a fixed arrangement of focusing elements over the arrangement of image icon elements such that the image icon elements (18, 20) project at least one synthetic image when viewed through the fixed arrangement of focusing elements; wherein the fixed arrangement of focusing elements has a first fixed lens pattern that forms a lens-icon pattern mismatched between the first fixed lens pattern and the patterns of the first and second contrasting materials (24, 32).