The Kodak verifax is a photo copying approach that uses a wet colloidal diffusion transfer technique patented by Yutzy, H.C. and Yackel, E.C.
Has a base that contains the recipient with the liquid developer and the exposure timer.
[3] Due to its extreme simplicity, the method was commonplace until the late 1960s, when it was surpassed by the popularity of the xerocopies using plain paper.
Copies had some chemical smell and lost contrast over time.
The DT (Diffusion transfer) was widespread in several countries since 1960:[2] Other products not specifically intended for copying, but employing a similar PMT technology include: Kodak Ektaflex (1981); Polaroid, sepia (1948), id, White Black (1950), id, color (1963)...