A one-pass process with combinations of charged and discharged area developments is used for three-level highlight color imaging. The process yields excellent gradation images between black and color because of perfect color registration. However, there are some special problems of fringe images, blurring, and appearance of white spots in the second color images, etc. Employing a very low resistance developer can overcome these problems. As a consequence, though, this type developer results in developing instability due to charge leakage. A highly stable three-level process without these problems is proposed which employs a higher resistance developer without charge leakage and applies a newly developed edge effect control technology and the first color developing station with dual rotation rollers. This process provides excellent highlight color images.
Teruaki Mitsuya, Hiroyuki Mabuchi, Masayoshi Ishii, Shinichi Akatsu, Yoshihiro Gunji, "Stabilized Three-Level Highlight Color Imaging with High Resistance Developer" in Journal of Imaging Science and Technology, 2001, pp 586 - 590, https://doi.org/10.2352/J.ImagingSci.Technol.2001.45.6.art00013