Question

Why is XcY color blind, but XcXC not color blind? Can an XcXC female pass the color blind trait to her children?

Answer 1

Somebody needs at least one XC to not be colorblind. XcY doesn't have XC, so they are colorblind. XcXC has XC, so they are not colorblind. (a colorblind female would need both to be colorblind - XcXc)

And XcXC female can pass colorblindless onto her children. For example, even if the father was a normal male (XCY), the one possible child could be XcY (with Xc from the mother and Y from the father), which doesn't have XC so its colorblind.