I think many people, even many artists, are confused by the term "Romanticism". I admit I was before studying the chapter on it. We generally think of the word "romantic" as a reference to matters of love and sensuality, of candle lit dinners, massages, and thoughtful surprises. But in a broader sense, Romanticism is an approach to life which is in contrast to that of logical pursuits.
Romanticism as an "ism" in art, then, focuses on the imagination and emotion and exhalts these above the strict observance of the natural world. This approach to creation isn't limited to producing only the sort of beauty we see in a sunset or in a baby's smile. Of particular interest to the romantics was that of the sublime. According to our textbook, "[Edmond] Burke observed that the most intense human emotions are evoked by pain or fear and that when these emotions are distanced, they can be thrilling." (pg. 660) This seems to be the best description of what truly drove the romantic artists to a great extent.
Beyond the sublime, and most surpising to me, Romanticists were also intrigued by and drawn to create dark and "nightmarish" imagery. Indeed, one of the examples in our book is entitled "The Nightmare". While beautifully executed, it exhibits a fascination with horror as it portrays a woman under the control of a demon, called an "incubus." Perhaps the artist most known for his horrific imagery is Goya. Having never studied this period of art, though familiar with the term "Romanticism", i was genuinely surprised that Goya was part of the Romantic movement. Again, it seems contradictory to what i naturally associate with Romance. While he doesn't, alone, define the Romantic movement, he was certainly a significant contributing member of it. And much of his imagery is dark and terrifying, and driven by such emotion.
Of all the movements following the renaissance, Romanticism seems to be the most notable transistion toward modern art. This is especially true of the philosphy associated with the movement. The notion of beauty had been challenged quite successfully, and much of the imagery produced, in retrospect, shows a new path toward modern ideals and concepts. I strongly doubt that artists (or anyone for that matter) of that time could, hypothetically, have travelled to the future, seen De Kooning's work and actually liked it or recognized the philosophy of romanticism to have had any influence on such work. But ultimately it did through the evolution of a philosophy, the seed of which was planted when imagination and emotion were deemed by some to take precedence over observation and idealism. In this regard, it's also worth noting that the painting styles of many Romanticists became much looser than their predecessors and contemporary neoclassicists. This, it seems, would eventually inspire future impressionists.