How to evaluate black and white photography?

Shao's "Water, Sky and Color", although the blank in the picture accounts for most of the picture, and the main ship accounts for a small part of the picture, due to the role of the background rope, the picture is virtual and real, dense and elegant, with a long and ethereal aesthetic feeling and fresh poetry, which gives people a relaxed feeling and increases the artistic appeal of high-profile works. The sand dunes in Weston are another scene. Gray occupies a large area, and the author uses the difference of light and shade to form different tone levels and light and shadow effects. The sand dunes in the picture are undulating, forming a beautiful pattern full of music rhythm. A deserted desert without plants has been treated so poetically that it can't be said that it is the result of photographer's climax aesthetic conception and photography technique. Li Peilin's work Mother's Sun, through low-key treatment, turns the background into black, darkens the mother's shadow, becomes a mountain, blocks the light of the children behind her, and becomes a "sun" rising in a ravine in Ran Ran, which expands and sublimates the theme of mother's hope for her son.