Symbolism, Imagery, Allegory
While it's true that Hemingway hates long sentences more than a bull hates bull-fighters, he still manages to paint some pretty literary pictures. We can thank his color palette for this.
Hemingway’s descriptions of the natural world are boldly sketched out in bright, clear colors. White roads, green fields, and the red tiled roofs of villages fill out the idealized landscape of Bill and Jake’s trip to Burguete, in contrast to the largely colorless, dimly lit interiors of Paris. Take a look-see:
In the Basque country the land all looks very rich and green and the houses and villages look well-off and clean… the houses in the villages had red tiled roofs, and then the road turned off and commenced to climb and we were going way up close along a hillside, with a valley below and hills stretched off back toward the sea. (10.4)
Ahh. How beautiful. How serene. How not like Paris.
This symbolizes the reawakening of the senses that Jake experiences as he leaves city life behind him, and heads toward the rejuvenating countryside.