Cloud

In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, ice crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water vapor primarily comprises these droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture from an adjacent source to raise the dew point to the ambient temperature. In the visual arts, the representation of clouds and the sky is known as a cloudscape. Although the term landscape painting suggests the land is the primary subject, it is frequently the sky and its clouds that make a composition intriguing, setting the tone and completely changing the overall mood of the work.

Throughout history, clouds have carried shifting iconographic and symbolic meanings. In the twelfth century, the cloud, then called a nue, was perceived theologically as the nuée mystique, or the veil of God, occasionally revealing paradise during a flash of light. More naturalistic perspectives classified them by color, with dark clouds seen as rain-bearing nimborum naves, or ships of rain, and white clouds as having emptied their water. Until the nineteenth century, clouds in the visual arts remained essentially in the domain of the sacred, serving as the hierophany for events like the ascension of Christ or visions of mystics. In Korean art, clouds carry different symbolism, specifically within the genre of the Ten Symbols of Longevity, where cumulus humilis clouds represent eternal youth and encapsulate harmony. Beyond specific symbols, clouds have long stimulated the human imagination due to their optical properties, development, and beauty.

The motif of the cloud appears in 544 works within the collection. These works span a variety of subjects and genres, from classical mythology to landscape and portraiture. Examples include mythological scenes such as Venus and Adonis, Venus and Mars, and Bacchus and Ariadne, as well as allegorical or figurative works like The Repose and Woman with a Parasol, Madame Monet and Her Son. Landscape representations make up a significant portion of the depictions, featuring in works like Lake Lucerne, Wivenhoe Park, Essex, Archery Contest, and Autumn, On the Hudson River. The breadth of these works demonstrates how clouds serve as a unifying atmospheric element across disparate themes and compositions.

The treatment of clouds in art has evolved significantly across periods and movements. During the Renaissance and Baroque periods, landscapes were unusual, though artists like El Greco utilized dramatic skies to enhance the emotional intensity of works like View of Toledo. In the Dutch Golden Age, painters such as Jacob van Ruisdael employed meticulous detail and contrasts of light and shadow to harmonize cloud masses with terrestrial subjects. The Romantic era, including the German Sturm und Drang movement, embraced the ephemeral and mobile character of clouds to convey the spirit of discovery and exploration, as seen in Caspar David Friedrich's Wanderer above the Sea of Fog. Luminism, an American art movement, utilized tranquil, featureless stratus clouds to emphasize light effects and atmospheric perspective. Later, Impressionists like Claude Monet focused on the fleeting energy and optical effects of weather. By the 1960s, artists like Georgia O'Keeffe began depicting clouds from an aerial, airplane perspective, using abstract methods that veered between pattern and landscape.

The artistic and cultural legacy of clouds bridges aesthetic representation and scientific observation. Before the nineteenth century, savants attempted to describe clouds subjectively, but their fugacity and complex nature obstructed categorization. This changed when Luke Howard proposed a scientific nephological system in 1803, utilizing universal Latin nomenclature that remains in use today. Howard's classification influenced artists, who increasingly incorporated scientific observations, sometimes drawn from balloon ascents, into their work. From the nineteenth century onward, artists like John Constable, Claude Monet, and Olafur Eliasson have utilized these scientific observations in their art. In literature, Charles Baudelaire represented clouds as the quintessence of the life of a stranger, loving them for their passing, marvelous nature. The continued relevance of clouds in both art and science is underscored by their role in climate sensitivity, where they remain a main uncertainty due to their dual capacity to reflect incoming solar rays for a cooling effect or trap longer wave radiation from the Earth's surface for a warming effect.