A CYYM filter is a

color filter array In digital imaging, a color filter array (CFA), or color filter mosaic (CFM), is a mosaic of tiny color filters placed over the pixel sensors of an image sensor to capture color information. The term is also used in reference to e paper devices ...

. It has one cyan, two yellow, and one magenta element. Developed by Kodak, it was used in the Kodak DCS 620x and DCS 720x DSLRs. http://www.fcenter.ru/online.shtml?articles/hardware/digitalphoto/4197

References

Color filter array {{photography-stub