diff --git a/internal/color.go b/internal/color.go
index 3c7ac2f..e8f0c4e 100644
--- a/internal/color.go
+++ b/internal/color.go
@@ -42,6 +42,8 @@ func (hsv HSV) RGBA () (r, g, b, a uint32) {
 	
 	h := clamp01(hsv.H) * 360
 	sector := int(h / 60)
+	// otherwise when given 1.0 for H, sector would overflow to 6
+	if sector > 5 { sector = 5 }
 	offset := (h / 60) - float64(sector)
 	
 	p  := component(v * (1 - s))