When I started restoring the Last Supper, I trusted the information obtained from the murals quite a bit, but I gradually stopped trusting information from the wall.
With regard to the color, I don’t think there is any final finish on the wall.
The Last Supper shows thirteen figures, including Jesus. Due to the large number of people, some apostles the colors of the clothes will be the same.
Most of the time, Jesus and John are the most important figures in the Last Supper, so their costumes are usually drawn in red and blue.
Moreover, these two people are always drawn side by side, so artists have to make a difference in the color of their clothes.
In the case of Jesus often used expensive vermilion and was usually drawn in bright and vivid red.
So I decided to express John’s mantle in a slightly darker red.