This paper challenges to a full-color-like reproduction from two primary color separations. In the mid 1950's, Edwin Land accidentally observed a colorful image on the screen projected from two red and green monochromatic separations lit by red and white illuminations. This phenomenon is well known as Land's two-color system, but why the so colorful image appears is not completely solved yet, but has stimulated the basic researches to explore the mystery behind the human color appearance.The motivation to the 2-color system started from an interest in solving a sort of ill-conditioned color estimation problem, not in the color vision theory. The paper tried to what extent a full-color-like reproduction is possible from a set of two-primary colors as a signal estimation problem. A simplified complementary 2-color system by Red/Cyan projections is newly proposedPaying an attention to the Red primary as most important, the proposed model demonstrates the excellent performance in a full-color-like reproduction from the Red/Cyan projections different from Red/White Land system. The paper discusses a reduction to 2color-to-2color from 2color-to-3color system. The simplified 2-color model may be applied to any 2-color print system with a cheap set of specified process color inks in the area of quick/convenience or newspaper printing industries.