diff --git a/src/kits/interface/ColorUtils.cc b/src/kits/interface/ColorUtils.cc
index d275ecf16f..b1baa403a7 100644
--- a/src/kits/interface/ColorUtils.cc
+++ b/src/kits/interface/ColorUtils.cc
@@ -26,30 +26,6 @@
 #include "ColorUtils.h"
 #include <stdlib.h>
 
-/*!
-	\brief An approximation of 31/255, which is needed for converting from 32-bit
-		colors to 16-bit and 15-bit.
-*/
-#define RATIO_8_TO_5_BIT .121568627451
-
-/*!
-	\brief An approximation of 63/255, which is needed for converting from 32-bit
-		colors to 16-bit.
-*/
-#define RATIO_8_TO_6_BIT .247058823529
-
-/*!
-	\brief An approximation of 255/31, which is needed for converting from 16-bit
-		and 15-bit colors to 32-bit.
-*/
-#define RATIO_5_TO_8_BIT 8.22580645161
-
-/*!
-	\brief An approximation of 255/63, which is needed for converting from 16-bit
-		colors to 32-bit.
-*/
-#define RATIO_6_TO_8_BIT 4.04761904762
-
 /*!
 	\brief Function for easy assignment of values to rgb_color objects
 	\param col Pointer to an rgb_color
@@ -92,9 +68,9 @@ void SetRGBColor15(rgb_color *col,uint16 color)
 	g16= (color >> 5) & 31;
 	b16= color & 31;
 
-	col->red=uint8(r16 * RATIO_5_TO_8_BIT);
-	col->green=uint8(g16 * RATIO_5_TO_8_BIT);
-	col->blue=uint8(b16 * RATIO_5_TO_8_BIT);
+	col->red=uint8(r16 << 3);
+	col->green=uint8(g16 << 3);
+	col->blue=uint8(b16 << 3);
 }
 
 /*!
@@ -118,9 +94,9 @@ void SetRGBColor16(rgb_color *col,uint16 color)
 	g16= (color >> 5) & 63;
 	b16= color & 31;
 
-	col->red=uint8(r16 * RATIO_5_TO_8_BIT);
-	col->green=uint8(g16 * RATIO_6_TO_8_BIT);
-	col->blue=uint8(b16 * RATIO_5_TO_8_BIT);
+	col->red=uint8(r16 << 3);
+	col->green=uint8(g16 << 2);
+	col->blue=uint8(b16 << 3);
 }
 
 /*!
@@ -193,9 +169,9 @@ uint16 FindClosestColor15(rgb_color color)
 	uint16 r16,g16,b16;
 	uint16 color16=0;
 	
-	r16=uint16(color.red * RATIO_8_TO_5_BIT);
-	g16=uint16(color.green * RATIO_8_TO_5_BIT);
-	b16=uint16(color.blue * RATIO_8_TO_5_BIT);
+	r16=uint16(color.red >> 3);
+	g16=uint16(color.green >> 3);
+	b16=uint16(color.blue >> 3);
 
 	// start with alpha value
 	color16=(color.alpha>127)?0x8000:0;
@@ -219,9 +195,9 @@ uint16 FindClosestColor16(rgb_color color)
 	uint16 r16,g16,b16;
 	uint16 color16=0;
 	
-	r16=uint16(color.red * RATIO_8_TO_5_BIT);
-	g16=uint16(color.green * RATIO_8_TO_6_BIT);
-	b16=uint16(color.blue * RATIO_8_TO_5_BIT);
+	r16=uint16(color.red >> 3);
+	g16=uint16(color.green >> 2);
+	b16=uint16(color.blue >> 3);
 
 	color16 |= r16 << 11;
 	color16 |= g16 << 5;