In true fresco painting the colour is put on the plaster only whilst it is still wet.

Michael Angelo must also have prepared a general scheme to scale from his small design, approved by the Pope, and set it off with very careful measurements on the surface of the rough cast, at least as to the architectural framework.

The cartoons for the figure-subjects and details he may have left until they were needed.

He considerably altered the scale of the figures in his stories as he proceeded with the work; this alteration in scale is not only observable in the central subjects or pictures of the vault, but also in the decorative figures on the framework, called Athletes; those at the end, near the stories of Noah and the Flood, and where Michael Angelo began to work, are at least a head smaller than those at the other end of the chapel over the altar, where the stories relate to the Creation.

This can be seen even in a photographic reproduction.