Today, I had a lesson of drawing and painting.
The teacher was an ex-lecturer of an art college. He taught us in one-by-one for a couple of hours at an atelier.
I drew a picture of a bamboo shoot. It was difficult for me to express its color and contrast on the surface of it.
The teacher told me that the upper part of an object usually should be painted with a light color compared with the lower side because the light illuminates the object from above.
Then, he adjusted my picture with a quick work. It became considerably improved immediately.
Artists have unique senses, I believe. They must see another scene than I in each moment.