Brown additive(c.1918–c.1930)

"[Little is currently known about this obscure process outside of the surviving film frames preserved at the Seaver Center for Western History Research (Natural History Museum of Los Angeles County), and the few sources listed in the References section. We welcome any leads readers may be able to provide.]"

Lloyd Brown’s invention relied on a reconfiguration of the size and position of frames onto 35mm film, which according to his patents, was intended for the reproduction of both B/W and color films. The patent describes that color images could be recorded on a regular 35mm B/W negative, capturing the same frame simultaneously in two colors (red and green), one above the other. The possibility of dividing the film in two, vertically, and pre-treating each side respectively with a red- or green-light sensitive emulsion was also mentioned, although this solution sounds unlikely from a practical point of view – the color records were most likely captured onto panchromatic film, through filters. 

On the print, the same frames were arranged in two parallel columns, one dyed red, the other green, and consecutive frames were positioned vertically, as on regular 35mm. The space traditionally allocated for one regular frame on 35mm would thus contain four smaller images. As seen on the frame samples, the film was likely advanced through the central perforation, positioned at the intersection of two consecutive frames and two parallel color columns. While the surviving samples from the Seaver Center for Western History Research showcase that the prints were tinted (Brown mentioned preferring dye baths to color his prints), the index card accompanying them misleadingly refers to “color being produced by a revolving red and blue-green filter in front of the projector”.