diff --git a/src/pkg/image/color/ycbcr.go b/src/pkg/image/color/ycbcr.go
index c6b9ba08db3..4c2f29ea021 100644
--- a/src/pkg/image/color/ycbcr.go
+++ b/src/pkg/image/color/ycbcr.go
@@ -87,9 +87,9 @@ func (c YCbCr) RGBA() (uint32, uint32, uint32, uint32) {
 }
 
 // YCbCrModel is the Model for Y'CbCr colors.
-var YCbCrModel Model = ModelFunc(modelYCbCr)
+var YCbCrModel Model = ModelFunc(yCbCrModel)
 
-func modelYCbCr(c Color) Color {
+func yCbCrModel(c Color) Color {
 	if _, ok := c.(YCbCr); ok {
 		return c
 	}