Sketch or black-and-white photography first.

Sketch comes first, then black-and-white photography, and painting takes precedence over photography.

Sketch is a kind of painting method that uses a relatively single color to express the object with the help of lightness change. Sketch painting tools are varied and not limited to one tool. Sketch is a relatively fast sketch form. Sketch level is one of the important indicators reflecting the basic level of painting and basic modeling ability of painters.