An apparatus (e.g., a multi-spectral optical filter array, an optical wafer, an optical component) has an aperture mask printed directly thereon, the aperture mask including a positive or negative photoresist. The apparatus includes a substrate having the aperture mask printed on at least one of a light entrance surface or a light exit surface of the substrate so as to provide an aperture over a portion of the substrate. The photoresist from which the aperture mask is formed is photo-definable or non-photo-definable, and is deposited/printed to form the aperture mask on the substrate.