| Number | Name | Date | Kind |
|---|---|---|---|
| 2449966 | Hansen | Sep 1948 | |
| 4992357 | Haga et al. | Feb 1991 | |
| 5364753 | Yamazaki et al. | Nov 1994 | |
| 5399468 | Sawyer et al. | Mar 1995 | |
| 5447831 | Singer et al. | Sep 1995 |
| Entry |
|---|
| Science and Technology of Photography. Karlheinz Keller, pp. 114-115, 1993. |
| Stroebel, et al "Photographic Materials and Processes", Focal Press, Boston/London 1986, Sect. 16.8 Color-Negative Masking, pp. 525-528. |