Historical tar finishes can be recreated by choosing the right kind of tar for the object, using compatible materials, and aiming for a maintainable surface rather than a modern sealed look.
A historical tar finish usually looks dark, practical, and weathered. It may be brown-black rather than pure black, matt rather than glossy, and uneven in a way that follows the grain and use of the object. The point is not to make everything look newly painted, but to give timber, rope, or canvas a believable treated surface.
Start by identifying the object and period. A maritime rope, a Scandinavian timber wall, a reenactment chest, a rustic tool handle, and a tarred canvas cover do not need the same finish. Pine tar, Stockholm tar, tar-oil blends, and other traditional mixtures behave differently and should be tested before committing to the final piece.
Recreation also means accepting limits. Many original finishes were maintained repeatedly and lived outdoors. A single fresh coat may smell too strong, look too shiny, or feel too sticky at first. Age, air, dust, sun, and handling all change the finish, so a convincing result often comes after settling rather than immediately after application.