Sapphire’s VintageColor3Strip filter simulates the color 3-strip film process from 1935 through 1955. Three-strip color was a subtractive process which exposed three separate film strips through color filters, then applied complementary color dyes to the print according to the density of the original records. This process was used for many films such as The Wizard Of Oz, Fantasia, and Gone With The Wind.
Modern color film has much broader color filtering in the emulsion layers, so this effect simulates the narrower filters and sharper colored dyes of the era which gave it its characteristic vibrancy. This effect also allows adding grain and color correction.