diff --git a/dCommon/NiColor.h b/dCommon/NiColor.h
index 585f0e5e8..e3065036d 100644
--- a/dCommon/NiColor.h
+++ b/dCommon/NiColor.h
@@ -9,26 +9,8 @@ struct NiColor {
 	constexpr NiColor(float red, float green, float blue) : m_Red(red), m_Green(green), m_Blue(blue) {}
 	constexpr NiColor() : NiColor(0.0f, 0.0f, 0.0f) {}
 
-	/* reduce RGB files to grayscale, with or without alpha
-	 * using the equation given in Poynton's ColorFAQ at
-	 * <http://www.inforamp.net/~poynton/> // dead link
-	 * Copyright (c) 1998-01-04 Charles Poynton poynton at inforamp.net
-	 *
-	 *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
-	 *
-	 *  We approximate this with
-	 *
-	 *     Y = 0.21268 * R    + 0.7151 * G    + 0.07217 * B
-	 *
-	 *  which can be expressed with integers as
-	 *
-	 *     Y = (6969 * R + 23434 * G + 2365 * B)/32768
-	 *
-	 *  The calculation is to be done in a linear colorspace.
-	 *
-	 *  Other integer coefficents can be used via png_set_rgb_to_gray().
-	 */
-	float ToXYZ() const { return (m_Red * 0.212671f) + (m_Green * 0.71516f) + (m_Blue * 0.072169f); };
+	// Relative luminance (Rec. 709 weights) of a linear color
+	constexpr float Luminance() const { return (m_Red * 0.212671f) + (m_Green * 0.71516f) + (m_Blue * 0.072169f); }
 };
 
 #endif // NICOLOR_H