Notice the tight corset, over large shoulders, and low waistline
The Infanta Margarita: This eight year old wears the old style of cartwheel fartigale (the roundness of her skirt) as to keep with Spanish style instead of moving to a more lax skirt style.
During this time a new, daring style of "undress" where women wore loosely fastened nightgowns over a voluminous chemise and tousled curls came to light due to the romanticized style originated by Anthony van Dyck in the 1630's. Often this style was for portraits only and rarely was wore on the streets or at court.
"Undress" a style of fashion of portraits which has strong influences in the Classical
A mantua: notice the flow from top to floor, the pattern of the fabric, and the fontange as the headpiece.
As far as hair goes, curls were definitely in. The curls were held in a bun early in the period, but finally hung gracefully on the shoulders in the later period. A fontange, of a frill cap of lace wired to stand in vertical tiers, often sat upon these curls. This headgear was named after a mistress of the French King Louis XIV, where it is said Madame Frontange was found with lace standing up in her hair after a outdoor "adventure" with the King. Nevertheless, this became a wildly popular female hairpiece for that time.
Helpful Links:
Bradley, Carolyn G. Western World Costume: An Outline History. New York: Appleton-Century-Crofts, 1954. Print.
Brown, Susan. Fashion: The Definitive History of Costume and Style. New York, NY: DK, 2012. Print.
Tortora, Phyllis G., and Keith Eubank. Survey of Historic Costume: A History of Western Dress. New York: Fairchild Publications, 1998. Print.
Tortora, Phyllis G., and Keith Eubank. Survey of Historic Costume: A History of Western Dress. New York: Fairchild Publications, 1998. Print.