This looks a Real Photo postcard (silver photographic process), but it is probably a gelatin process (collotype) card. The card is damaged on the right edge and has a stain on the bottom in the middle. The words "Hotel-St. Catherine" in white at the bottom would have been scratched onto the image during its development, appearing the same color as the paper. Construction was begun on the Hotel St. Catherine in 1917 to replace the Metropole, destroyed by a fire in 1915 that burned a third of Avalon. By 1918 it was open for business. The surrounding Descanso Canyon shows in the background. The approximate date is 1919.