The last supper is what gives the basis of the Eucharist according to the scriptures Therefore Leonardo used this tradition to form the basis for his painting. Leonardo's painting the last supper was principally divided into three groups the first group was made up of Bartholomew, James the lesser and Andrew from the first group of three, here they ball appear surprised and Andrew holds his hands up in front of him in a gesture that depicted that he was frightened. The second group is made up of judas, simon peter and John .Judas here is holding a silver bag in his right hand and at the same time reaching with his left hand a piece of bread.simon peter leaning over Johns shoulder and holding a knife in his right hand symbolizes his readiness to defend Jesus while John appears to be swooning. This goes against the tradition since Judas was isolated from the rest of the apostles in previous works either through sating across the table from Jesus or on one side or even by giving all other apostles excluding him. He even created a dramatic and subtle effect through swathing Judas in shadow. He also made a realistic explanation of the prophetic work of Christ of the first man to share bread with him would betray him. Judas and Jesus are seen to b e reaching to the same bread though no one seems to be paying attention to this. The third group is of Thomas, James the great and Philip. They all appear to be in shock but in varying degrees Thomas has his hands raised, Philip is sorting for an explanation while James is recoiling in horror from Jesus. The fourth group is Matthew, Jude Thaddeus and Simon zealot who appear to be in a discussion.

Fresco painting is whereby water-based pigments are painted on freshly applied plaster that is on wall surfaces. The colors are prepared from grinding dry powder pigments in pure water; they...

This was a point that he used in the emphasis of the central position of Christ. All lines converge on the eyes of Christ and hence everyone looking at the paint will focus on this place. The painting was naturalistic since he had an interest in anatomy and hence he was able to paint figures that were accurate in details in all forms and proportions. There were also various looks of shock, confusion and distraught that showed clearly naturalism in Leonardo's work.
Judas was depicted as reaching towards the plate beside jesus and not as in earlier works as detached from the other apostles. Also the fact that he is clutching onto a purse is the reward that he will get for his identification of Christ to authorities. John is portrayed as swoon since he is not sure of what is ahead and hence he is in shock. Jesus is depicted as being central of the whole pain ting and all attention is drawn towards him since he is the one who will be the victim of betrayal and eventual death.

King says that Leonardo's Last Supper is regarded as a landmark painting this is because the disciples were displayed in human form and emotions that could be identified and it was the first one to depict real people. Also the technical perspective in the last supper was very incredible since every single element of the painting directs attention to the central point of the work which is Christ.

Reference

Nicholl, C.(2012). The guardian. Leonardo and the Last Supper by Ross King -- review. Retrieved February 3, 2013 from http://www.guardian.co.uk/books/2012/oct/19/leonardo-last-supper-ross-king-review