diff --git a/code/nel/tools/3d/panoply_maker/color_modifier.cpp b/code/nel/tools/3d/panoply_maker/color_modifier.cpp
index a55936b7c..b34e021ed 100644
--- a/code/nel/tools/3d/panoply_maker/color_modifier.cpp
+++ b/code/nel/tools/3d/panoply_maker/color_modifier.cpp
@@ -46,7 +46,7 @@ void CColorModifier::convertBitmap(NLMISC::CBitmap &destBitmap, const NLMISC::CB
 	
 	
 	const NLMISC::CRGBA  *src   = (NLMISC::CRGBA *) &srcBitmap.getPixels()[0];
-	const NLMISC::CRGBA  *mask =  (NLMISC::CRGBA *) &maskBitmap.getPixels()[0];
+	const uint8  *mask =  &maskBitmap.getPixels()[0];
 		  NLMISC::CRGBA  *dest =  (NLMISC::CRGBA *) &destBitmap.getPixels()[0];
 	
 
@@ -69,7 +69,7 @@ void CColorModifier::convertBitmap(NLMISC::CBitmap &destBitmap, const NLMISC::CB
 			result.B = CalcBrightnessContrast(result.B, Luminosity, Contrast, grey);
 
 			// blend to the destination by using the mask alpha			
-			result.blendFromui(*dest, result, mask->R);
+			result.blendFromui(*dest, result, *mask);
 
 			/// keep alpha from the source			
 			dest->R = result.R;
@@ -111,7 +111,7 @@ void CColorModifier::evalBitmapStats(const NLMISC::CBitmap &srcBitmap,
 	float gTotal  = 0;	
 
 	const NLMISC::CRGBA *src = (NLMISC::CRGBA *) &srcBitmap.getPixels()[0];
-	const NLMISC::CRGBA *mask = (NLMISC::CRGBA *) &maskBitmap.getPixels()[0];
+	const uint8 *mask = &maskBitmap.getPixels()[0];
 
 	for (uint y = 0; y < srcBitmap.getHeight(); ++y)
 	{
@@ -119,7 +119,7 @@ void CColorModifier::evalBitmapStats(const NLMISC::CBitmap &srcBitmap,
 		{
 			float h, l, s;
 		
-			float intensity = mask->R * (1.f / 255.f);			
+			float intensity = *mask * (1.f / 255.f);			
 			bool achromatic = src->convertToHLS(h, l, s);
 
 			float grey = 0.299f * src->R + 0.587f * src->G + 0.114f * src->B;
diff --git a/code/nel/tools/3d/panoply_maker/hls_bank_texture_info.cpp b/code/nel/tools/3d/panoply_maker/hls_bank_texture_info.cpp
index 2fc50d28f..4e6a1693a 100644
--- a/code/nel/tools/3d/panoply_maker/hls_bank_texture_info.cpp
+++ b/code/nel/tools/3d/panoply_maker/hls_bank_texture_info.cpp
@@ -43,18 +43,15 @@ void			CHLSBankTextureInfo::serial(NLMISC::IStream &f)
 // ***************************************************************************
 void		CHLSBankTextureInfo::CMaskBitmap::build(const NLMISC::CBitmap &src)
 {
-	nlassert(src.getPixelFormat()==CBitmap::RGBA);
+	nlassert(src.getPixelFormat()==CBitmap::Luminance);
 	Width= src.getWidth();
 	Height= src.getHeight();
 	Pixels.resize(Width*Height);
 	if(!Pixels.empty())
 	{
-		CRGBA	*pSrc= (CRGBA*)(&src.getPixels()[0]);
-		uint8	*pDst= &Pixels[0];
-		for(uint i=0; i<Pixels.size(); i++)
-		{
-			pDst[i]= pSrc[i].R;
-		}
+		uint8	*pSrc = (uint8*)src.getPixels().getPtr();
+		uint8	*pDst = &Pixels[0];
+		memcpy(pDst, pSrc, Pixels.size());
 	}
 }
 
diff --git a/code/nel/tools/3d/panoply_maker/panoply_maker.cpp b/code/nel/tools/3d/panoply_maker/panoply_maker.cpp
index 12f2aa231..e3fb126db 100644
--- a/code/nel/tools/3d/panoply_maker/panoply_maker.cpp
+++ b/code/nel/tools/3d/panoply_maker/panoply_maker.cpp
@@ -795,8 +795,38 @@ static void BuildColoredVersionForOneBitmap(const CBuildInfo &bi, const std::str
 					// masks can be converted to grayscale files
 					if (bi.OptimizeTextures > 0 && maskDepth > 8)
 					{
+						if (!li.Mask.isGrayscale())
+						{
+							nlwarning("Mask %s is using colors, results may by incorrect! Use OptimizeTextures = 2 to fix it.", maskFileName.c_str());
+						}
+
 						if (bi.OptimizeTextures > 1)
 						{
+							// get a pointer on original data
+							uint32 size = li.Mask.getPixels().size();
+							uint32 *data = (uint32*)li.Mask.getPixels().getPtr();
+							uint32 *endData = (uint32*)((uint8*)data + size);
+
+							NLMISC::CRGBA *color = NULL;
+
+							// process all pixels
+							while(data < endData)
+							{
+								color = (NLMISC::CRGBA*)data;
+
+								// copy red value to green and blue,
+								// because only red is used for mask
+								color->B = color->G = color->R;
+
+								// make opaque
+								color->A = 255;
+
+								++data;
+							}
+
+							// convert image to real grayscale
+							li.Mask.convertToType(NLMISC::CBitmap::Luminance);
+
 							NLMISC::COFile os;
 
 							if (os.open(maskFileName))
@@ -826,9 +856,9 @@ static void BuildColoredVersionForOneBitmap(const CBuildInfo &bi, const std::str
 						}
 					}
 
-					if (li.Mask.PixelFormat != NLMISC::CBitmap::RGBA)
+					if (li.Mask.PixelFormat != NLMISC::CBitmap::Luminance)
 					{
-						li.Mask.convertToType(NLMISC::CBitmap::RGBA);
+						li.Mask.convertToType(NLMISC::CBitmap::Luminance);
 					}
 
 					/// make sure the mask has the same size
@@ -969,5 +999,4 @@ static void BuildColoredVersionForOneBitmap(const CBuildInfo &bi, const std::str
 	{
 		nlerror("Couldn't write %s", fullHlsInfoPath.c_str());
 	}
-
 }