Romanticism-
The period is more scientific and rational in nature. Romanticism, captures and represents a sublime moment or experience.
Shelley's use of Romanticism emphasises realism and real issues. For instance, emotions such as love, horror, sorrow, etc are detailed through her work. If you think of logical/rational vs emotional/irrational, the latter would best reflect the romantic era. Considering that the novel is about a creature that terrifies people and has those emotional connotations and connections associated with it, it's a sort of self-evident example of romanticism.
Two classic characters that are representative of this movement within Shelley's novel are Henry Clerval and the creature. For e.g. one quote that supports the romantic movement from the creature being; "I vowed hatred upon all mankind."
Enlightenment-
Social Justice, especially in the characters of Justine ( her name being symbolic of "justice") and the DeLaceys -- are firmly rooted in the Enlightenment.
Primitive life- The scene where the creature is learning the fundamentals of life; like a child taking its first steps. Can also be alikened to Maslow's hierarchy of basic needs.
Scientific Conception of Knowledge- "Truth" through math and evidence.
Victor Frankenstein's role as the character of enlightment pulled him out of nature, but made him a slave to his creation.
Symbols of light and fire representative of Shelley's fact of enlightenment as well, e.g. The Modern Prometheus and the fire that the creature builds. Symbols of optimism and hope/freedom.
