What are the shading techniques called?

In the artwork "that gentleman" by andrew wyeth how intense are the colors? what are their individual values and temperature?

Read the excerpt from act l, scene i of romeo and juliet. what is the cause of romeo's despair? benvolio: groan! why, no; but sadly tell me who romeo has wronged benvolio. romeo misses his friends and family romeo wants to fight the capulets. romeo is in love with a woman romeo: bid a sick man in sadness make his will: ah! word ill urg'd to one that is so ill. in sadness, cousin, i do love a woman save and exit

The merode altarpiece by robert campin in what way did this painting make art history?