There is described a security element (EL) or document (BN), such as a banknote, comprising (i) a substrate (S) with first and second sides (I, II) and exhibiting at least one window region (W) made of a substantially transparent material, (ii) a micro-optical structure (OP) provided on the first side (I) of the substrate (S) and extending over at least a part of the window region (W), and (iii) a printed feature (P1-P3) printed on the second side (II) of the substrate (S) over at least a part of the window region (W), the printed feature (P1-P3) being provided in register with the micro-optical structure (OP) to produce an optically-variable effect (EF) upon looking at the printed feature (P1-P3) from the first side (I) of the substrate (S) through the micro-optical structure (OP) and the window region (W). The security element (EL) or document (BN) further comprises a protective layer (L) acting as printable primer layer and provided on the second side (II) of the substrate (S) over the window region (W) and on top of the printed feature (P1-P3), which protective layer (L) covers the printed feature (P1-P3) when seen from the second side (II) of the substrate (S) and further acts as a contrast-enhancing layer for the optically-variable effect (EF).