Michelangelo applied a thin, white layer of plaster over the initial violet- colored application of plaster for what reason?
To produce actual texture.
To assist in the drying process.
To create a way to correct mistakes.
To allow the colors to be as bright as possible.

Depending on the situation... NORMALLY it is a way to correct mistakes and create a smoother surface to fix an imperfection

Explanation:

the sculpture i am pretty sure you are talking about is the statue b. the david statue now lives in the galleria dell'accademia, florence, italy. it was made by ‎michelangelo.