In the left panel, SSPs with different ages and metallicities are from BC03. The first 10 SSPs have different ages but the same metallicity (solar metallicity), and the last 5 SSPs have the same age (5 Gyr) but different metallicities. They are normalized at 5500 Å, and the ith SSP has been shifted upward i − 1 units. The right panel shows the ratios of the small- to large-scale component of each SSPs, and the ith is shifted upward i − 1 units.