Begin with the wall
Leonardo’s *Last Supper* is in Milan, in the refectory of Santa Maria delle Grazie. The official museum describes it as dry wall-painting, not simply tempera applied to stone and not conventional painting into wet plaster. Its work record identifies the object and technique.
The museum’s conservation explanation describes pigments applied over a prepared dry surface and the early deterioration of the work.
What could a different technique change?
It is reasonable to ask how different materials might affect durability. It is not possible to assume that changing one technique would preserve an otherwise identical painting perfectly for centuries.
The method of working can affect the image itself: the time available for a passage, how revisions are made and how an artist develops details. A counterfactual must therefore ask whether it is imagining the same composition made differently or a different painting altogether.
A conservation exercise
Read the museum’s description and make three lists: material choices, later conditions and modern interventions. Keep them separate. Damage is not always explained by the artist’s initial decision alone.
Then write a short alternative beginning at the point of production. Explain the artistic trade-off as well as the hoped-for benefit. Avoid assigning modern conservation knowledge to a historical participant unless you explicitly make that part of a fantasy.
Why objects matter
A surviving artwork has a history after its maker leaves it. Studying that history offers a more precise question than imagining a generally more productive Leonardo: how do material decisions and later care shape what future viewers can see?
Editorial review
Reviewed on 26 September 2026. Corrected the wall-painting technique and gave this overlapping article a distinct conservation focus.