A method of making a physical object by additive manufacturing. The method has the steps of providing a light hardenable primary material (11), building up the object (100) by successively hardening portions of the light hardenable primary material (11) by irradiating the portions with light, coating at least a part of the object (100) with a light permeable coating or oxygen protective material; and irradiating the coated object (100) with light and thereby post-hardening any light hardenable material (11).