diff --git a/rtdata/languages/default b/rtdata/languages/default
index 1680c21a2..5e434d81a 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -451,6 +451,8 @@ PREFERENCES_DIRSOFTWARE;Installation directory
 PREFERENCES_DMETHOD;Method
 PREFERENCES_EDITORCMDLINE;Other command line
 PREFERENCES_EDITORLAYOUT;Editor Layout
+PREFERENCES_EXPOS;Exposure before interpolation\n :correction (lin)
+PREFERENCES_PRESER;Exposure before interpolation\n :preserve highlights (EV)
 PREFERENCES_EXTERNALEDITOR;External editor
 PREFERENCES_FALSECOLOR;False color suppression steps
 PREFERENCES_FBROWSEROPTS;File Browser Options
diff --git a/rtengine/expo_before_b.cc b/rtengine/expo_before_b.cc
new file mode 100644
index 000000000..a19329ece
--- /dev/null
+++ b/rtengine/expo_before_b.cc
@@ -0,0 +1,111 @@
+
+////////////////////////////////////////////////////////////////
+//
+//		//exposure correction before interpolation
+//
+//  code dated: December 27, 2010
+//
+//	Expo_before.cc is free software: you can redistribute it and/or modify
+//	it under the terms of the GNU General Public License as published by
+//	the Free Software Foundation, either version 3 of the License, or
+//	(at your option) any later version.
+//
+//	This program is distributed in the hope that it will be useful,
+//	but WITHOUT ANY WARRANTY; without even the implied warranty of
+//	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//	GNU General Public License for more details.
+//
+//	You should have received a copy of the GNU General Public License
+//	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+////////////////////////////////////////////////////////////////
+//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+//		     Jacques Desmis <jdesmis@gmail.com>
+//   	     use fast-demo(provisional) from Emil Martinec
+//			 inspired from work Guillermo Luijk and Manuel LLorens(Perfectraw)
+// I use OMP
+  // This function uses parameters:
+  //      exposure (lineal): 2^(-8..0..8): currently 0.5 +3
+  //      preserve (log)   : 0..8 : currently 0.1 1
+
+//modi : 31/12/2010
+#define LIM(x,min,max) MAX(min,MIN(x,max))
+#define CLIPF(x) LIM(x,0.0,65535.0)
+
+void RawImageSource::exp_bef(float expos, float preser) {
+	double dt,dT2;
+	clock_t t1, t2,t3,t4,t5;
+	float Yp, exposure2, K, EV;
+//	float LUT[65536];
+float *LUT = new float[65536];
+	int i;
+	int row,col;
+	int width=W, height=H;
+
+	// I use with Dcraw FDD interpolate from Luis Sanz , very fast and good, one can change for another : here with Rawtherpee == fastdemo() from Emil Martinec
+	//t1 = clock();
+	 //float *img = new float[H*W];//to save configuration : with RT is it necessary ??
+		unsigned short** imgd; 
+		imgd = allocArray< unsigned short >(W,H);//with memcpy : faster than for (...)
+		for (int i=0; i<H; i++) {
+				memcpy (imgd[i], rawData[i], W*sizeof(**imgd));}//save configuration but perhaps instable...
+	 
+	 fast_demo (0,0,W,H);//from Emil
+// calculate CIE luminosity
+float *YY;
+YY = (float *)calloc(width*height,sizeof *YY);// for CIE luminosity
+#pragma omp parallel default(shared)  
+{
+#pragma omp for  
+	 for(int row=0;row<height;row++)
+		for(int col=0;col<width;col++)
+			{int i=row*width+col;
+			YY[i]=CLIPF(0.299*(float)red[row][col]+0.587*(float)green[row][col]+0.114*(float)blue[row][col]); // CIE luminosity
+				}
+}	
+
+		for (int i=0; i<H; i++) {
+				memcpy (rawData[i], imgd[i], W*sizeof(**imgd));}//restore config
+			
+freeArray<unsigned short>(imgd, H);//free memory imgd
+
+	//exposure correction inspired from G.Luijk
+ if(preser==0.0){	// protect highlights 
+#pragma omp parallel for  shared(expos)
+	 for(int row=0;row<height;row++)
+		for(int col=0;col<width;col++)
+			{rawData[row][col]=CLIPF((float)rawData[row][col]*expos);}
+  }else{
+    // Exposure correction with highlight preservation
+    if(expos>1){
+      K=65535/expos*exp(-preser*log((double) 2));
+      for(int j=0;j<=65535;j++) LUT[(int)j]=CLIPF(((65535-K*expos)/(65535-K)*(j-65535)+65535)/j);
+
+#pragma omp parallel for  shared(expos)
+	 for(int row=0;row<height;row++)
+		for(int col=0;col<width;col++){
+			if(YY[row*width+col]<K){
+				rawData[row][col]=CLIPF((float)rawData[row][col]*expos);}
+			else{
+				float exposure2=LUT[(int)YY[row*width+col]];
+				rawData[row][col]=CLIPF((float)rawData[row][col]*exposure2);}}
+			}
+	else{
+      float EV=log(expos)/log(2.0);                              // Convert exp. linear to EV
+      float K=65535.0*exp(-preser*log((double) 2));
+      for(int j=0;j<=65535;j++) LUT[(int)j]=CLIPF(exp(EV*(65535.0-j)/(65535.0-K)*log((double) 2)));
+#pragma omp parallel for  shared(expos)	  
+	 for(int row=0;row<height;row++)
+		for(int col=0;col<width;col++){
+			if(YY[row*width+col]<K){
+				rawData[row][col]=CLIPF((float)rawData[row][col]*expos);}
+			else{
+				float exposure2=LUT[(int)YY[row*width+col]];
+				rawData[row][col]=CLIPF((float)rawData[row][col]*exposure2);}}
+    }	
+}
+free(YY);
+delete [] LUT;
+
+}
\ No newline at end of file
diff --git a/rtengine/procparams.cc b/rtengine/procparams.cc
index a4e9aa16e..99fa59409 100644
--- a/rtengine/procparams.cc
+++ b/rtengine/procparams.cc
@@ -210,7 +210,11 @@ void ProcParams::setDefaults () {
     raw.dmethod = RAWParams::methodstring[RAWParams::hphd];;
     raw.dcb_iterations=2;
     raw.dcb_enhance=false;
-
+	//exposition
+raw.expos=1.0;
+raw.preser=0.0;
+//raw.expos_correc=false;
+// expos
     exif.clear ();
     iptc.clear ();
     
@@ -435,6 +439,12 @@ int ProcParams::save (Glib::ustring fname) const {
     keyFile.set_string  ("RAW", "Method", raw.dmethod );
     keyFile.set_integer ("RAW", "DCBIterations", raw.dcb_iterations );
     keyFile.set_boolean ("RAW", "DCBEnhance", raw.dcb_enhance );
+	//exposition
+//	keyFile.set_boolean ("RAW", "PreExpo", raw.expos_correc );
+    keyFile.set_double ("RAW", "PreExposure", raw.expos );
+    keyFile.set_double ("RAW", "PrePreserv", raw.preser );
+
+	// exposition
 
     // save exif change list
     for (int i=0; i<(int)exif.size(); i++)
@@ -752,6 +762,11 @@ if (keyFile.has_group ("RAW")) {
 	if (keyFile.has_key ("RAW", "Method"))        raw.dmethod = keyFile.get_string ("RAW", "Method");
 	if (keyFile.has_key ("RAW", "DCBIterations")) raw.dcb_iterations = keyFile.get_integer("RAW", "DCBIterations");
 	if (keyFile.has_key ("RAW", "DCBEnhance"))    raw.dcb_enhance =keyFile.get_boolean("RAW", "DCBEnhance");
+//	if (keyFile.has_key ("RAW", "PreExpo"))   		  raw.expos_correc =keyFile.get_boolean("RAW", "PreExpo");//exposi
+	if (keyFile.has_key ("RAW", "PreExposure"))   	  raw.expos =keyFile.get_double("RAW", "PreExposure");
+	if (keyFile.has_key ("RAW", "PrePreserv"))   	  raw.preser =keyFile.get_double("RAW", "PrePreserv");
+	
+
 }
 
     // load exif change settings
@@ -951,7 +966,9 @@ bool ProcParams::operator== (const ProcParams& other) {
 	&& dirpyrequalizer == other.dirpyrequalizer
 	&& hsvequalizer == other.hsvequalizer
         && exif==other.exif
-        && iptc==other.iptc;
+        && iptc==other.iptc
+	&& raw.expos==other.raw.expos  // exposi
+	&& raw.preser==other.raw.preser; 
 }
 
 bool ProcParams::operator!= (const ProcParams& other) {
diff --git a/rtengine/procparams.h b/rtengine/procparams.h
index 16d137fe0..c5d91588a 100644
--- a/rtengine/procparams.h
+++ b/rtengine/procparams.h
@@ -395,6 +395,9 @@ class RAWParams {
 		bool ca_autocorrect;
 		double cared;
 		double cablue;
+	//	bool expos_correc;
+		double expos;
+		double preser; // expos
 		bool hotdeadpix_filt;
 		int	linenoise;
 		int greenthresh;
diff --git a/rtengine/rawimagesource.cc b/rtengine/rawimagesource.cc
index 3a3b725be..6505cf0ae 100644
--- a/rtengine/rawimagesource.cc
+++ b/rtengine/rawimagesource.cc
@@ -951,8 +951,18 @@ void RawImageSource::preprocess  (const RAWParams &raw)
 			plistener->setProgress (0.0);
 		}
 		
-		CA_correct_RT(raw.cared, raw.cablue);
+		CA_correct_RT(raw.cared, raw.cablue);		
 	}
+	
+	if ( raw.expos !=1 ) { // exposure
+		if (plistener) {
+			plistener->setProgressStr ("Exposure Correction...");
+			plistener->setProgress (0.0);
+		}		
+		exp_bef(raw.expos, raw.preser);
+		
+	}
+	
     t2.set();
     if( settings->verbose )
        printf("Preprocessing: %d µsec\n", t2.etime(t1));
@@ -3204,6 +3214,8 @@ void RawImageSource::dcb_demosaic(int iterations, int dcb_enhance)
 #include "CA_correct_RT.cc"//Emil's CA auto correction
 #include "cfa_linedn_RT.cc"//Emil's CA auto correction
 #include "green_equil_RT.cc"//Emil's green channel equilibration
+#include "expo_before_b.cc"//Jacques's exposure before interpolation
+
 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 
diff --git a/rtengine/rawimagesource.h b/rtengine/rawimagesource.h
index faffd3b5c..20995f486 100644
--- a/rtengine/rawimagesource.h
+++ b/rtengine/rawimagesource.h
@@ -150,6 +150,8 @@ class RawImageSource : public ImageSource {
 
         int  LinEqSolve( int nDim, float* pfMatr, float* pfVect, float* pfSolution);//Emil's CA auto correction
         void CA_correct_RT	(double cared, double cablue);
+		void exp_bef (float expos, float preser);//exposi
+		
         int  cfaCleanFromMap( BYTE* bitmapBads );
         int  findHotDeadPixel( BYTE *bpMap, float thresh);
         void ddct8x8s(int isgn, float **a);
diff --git a/rtgui/paramsedited.cc b/rtgui/paramsedited.cc
index 822512523..a5b92cffd 100644
--- a/rtgui/paramsedited.cc
+++ b/rtgui/paramsedited.cc
@@ -288,6 +288,9 @@ void ParamsEdited::initFrom (const std::vector<rtengine::procparams::ProcParams>
         raw.caCorrection = raw.caCorrection && p.raw.ca_autocorrect == other.raw.ca_autocorrect;
 		raw.caRed = raw.caRed && p.raw.cared == other.raw.cared;
         raw.caBlue = raw.caBlue && p.raw.cablue == other.raw.cablue;
+	//	raw.exCorrection = raw.exCorrection && p.raw.expos_correc == other.raw.expos_correc;
+		raw.exPos = raw.exPos && p.raw.expos == other.raw.expos;
+		raw.exPreser = raw.exPreser && p.raw.preser == other.raw.preser; //exposi
         raw.darkFrame = raw.darkFrame && p.raw.dark_frame == other.raw.dark_frame;
         raw.dfAuto = raw.dfAuto && p.raw.df_autoselect == other.raw.df_autoselect;
         raw.greenEq = raw.greenEq && p.raw.greenthresh == other.raw.greenthresh;
@@ -434,6 +437,8 @@ void ParamsEdited::combine (rtengine::procparams::ProcParams& toEdit, const rten
     if (raw.caCorrection)       toEdit.raw.ca_autocorrect = mods.raw.ca_autocorrect;
 	if (raw.caRed)				toEdit.raw.cared    = mods.raw.cared;
     if (raw.caBlue)				toEdit.raw.cablue    = mods.raw.cablue;
+	if (raw.exPos)				toEdit.raw.expos     =mods.raw.expos;
+	if (raw.exPreser)			toEdit.raw.preser     =mods.raw.preser;	
     if (raw.greenEq)            toEdit.raw.greenthresh  = mods.raw.greenthresh;
     if (raw.hotDeadPixel)       toEdit.raw.hotdeadpix_filt= mods.raw.hotdeadpix_filt;
     if (raw.linenoise)          toEdit.raw.linenoise    = mods.raw.linenoise;
diff --git a/rtgui/paramsedited.h b/rtgui/paramsedited.h
index 2c77ab3fe..b0de09599 100644
--- a/rtgui/paramsedited.h
+++ b/rtgui/paramsedited.h
@@ -287,6 +287,9 @@ class RAWParamsEdited {
         bool linenoise;
         bool darkFrame;
         bool dfAuto;
+		bool exCorrection;
+		bool exPos;
+		bool exPreser;
 };
 
 class ExifPairEdited {
diff --git a/rtgui/preprocess.cc b/rtgui/preprocess.cc
index c07edb951..bac00850e 100644
--- a/rtgui/preprocess.cc
+++ b/rtgui/preprocess.cc
@@ -43,6 +43,14 @@ PreProcess::PreProcess ()
 	caBlue = Gtk::manage(new Adjuster (M("PREFERENCES_CABLUE"),-4.0,4.0,0.1,0));
 	caBlue->setAdjusterListener (this);
 	caBlue->show();
+//exposi
+	exPos = Gtk::manage(new Adjuster (M("PREFERENCES_EXPOS"),0.2,4.0,0.1,1));
+	exPos->setAdjusterListener (this);
+	exPos->show();
+	exPreser = Gtk::manage(new Adjuster (M("PREFERENCES_PRESER"),0,2.5,0.1,0));
+	exPreser->setAdjusterListener (this);
+	exPreser->show();
+
 	
 	hotDeadPixel = Gtk::manage(new Gtk::CheckButton((M("PREFERENCES_HOTDEADPIXFILT"))));
 
@@ -62,6 +70,9 @@ PreProcess::PreProcess ()
     pack_start( *caAutocorrect, Gtk::PACK_SHRINK, 4);
 	pack_start( *caRed, Gtk::PACK_SHRINK, 4);
     pack_start( *caBlue, Gtk::PACK_SHRINK, 4);
+	pack_start( *exPos, Gtk::PACK_SHRINK, 4);//exposi
+    pack_start( *exPreser, Gtk::PACK_SHRINK, 4);
+	
     pack_start( *Gtk::manage (new  Gtk::HSeparator()));
     pack_start( *lineDenoise, Gtk::PACK_SHRINK, 4);
     pack_start( *Gtk::manage (new  Gtk::HSeparator()));
@@ -87,6 +98,9 @@ void PreProcess::read(const rtengine::procparams::ProcParams* pp, const ParamsEd
 	   caAutocorrect->set_inconsistent(!pedited->raw.caCorrection);
 	   caRed->setEditedState( pedited->raw.caRed ? Edited : UnEdited );
 	   caBlue->setEditedState( pedited->raw.caBlue ? Edited : UnEdited );
+	   exPos->setEditedState( pedited->raw.exPos ? Edited : UnEdited );
+	   exPreser->setEditedState( pedited->raw.exPreser ? Edited : UnEdited );
+	   //exposi
 	   hotDeadPixel->set_inconsistent (!pedited->raw.hotDeadPixel);
 	   lineDenoise->setEditedState( pedited->raw.linenoise ? Edited : UnEdited );
 	   greenEqThreshold->setEditedState( pedited->raw.greenEq ? Edited : UnEdited );
@@ -105,6 +119,8 @@ void PreProcess::read(const rtengine::procparams::ProcParams* pp, const ParamsEd
    caAutocorrect->set_active(pp->raw.ca_autocorrect);
 	caRed->setValue (pp->raw.cared);
 	caBlue->setValue (pp->raw.cablue);
+	exPos->setValue (pp->raw.expos);
+	exPreser->setValue (pp->raw.preser);//exposi
    hotDeadPixel->set_active (pp->raw.hotdeadpix_filt);
    lineDenoise->setValue (pp->raw.linenoise);
    greenEqThreshold->setValue (pp->raw.greenthresh);
@@ -126,6 +142,9 @@ void PreProcess::write( rtengine::procparams::ProcParams* pp, ParamsEdited* pedi
 	pp->raw.ca_autocorrect = caAutocorrect->get_active();
 	pp->raw.cared = (double)caRed->getValue();
 	pp->raw.cablue = (double)caBlue->getValue();
+	pp->raw.expos = (double)exPos->getValue();
+	pp->raw.preser = (double)exPreser->getValue();//exposi
+	
 	pp->raw.hotdeadpix_filt = hotDeadPixel->get_active();
 	pp->raw.linenoise = (int)lineDenoise->getValue();
 	pp->raw.greenthresh = (int)greenEqThreshold->getValue();
@@ -138,6 +157,10 @@ void PreProcess::write( rtengine::procparams::ProcParams* pp, ParamsEdited* pedi
 		pedited->raw.caCorrection = !caAutocorrect->get_inconsistent();
 		pedited->raw.caRed = caRed->getEditedState ();
 		pedited->raw.caBlue = caBlue->getEditedState ();
+		//pedited->raw.exCorrection = !caAutocorrect->get_inconsistent();
+		pedited->raw.exPos = exPos->getEditedState ();
+		pedited->raw.exPreser = exPreser->getEditedState ();//exposi
+		
 		pedited->raw.hotDeadPixel = !hotDeadPixel->get_inconsistent();
 	}
 }
@@ -153,6 +176,8 @@ void PreProcess::setBatchMode(bool batchMode)
    ToolPanel::setBatchMode (batchMode);
 	caRed->showEditedCB ();
 	caBlue->showEditedCB ();
+	exPos->showEditedCB ();
+	exPreser->showEditedCB ();//exposi
    lineDenoise->showEditedCB ();
    greenEqThreshold->showEditedCB ();
 }
@@ -162,16 +187,25 @@ void PreProcess::setDefaults(const rtengine::procparams::ProcParams* defParams,
 	lineDenoise->setDefault( defParams->raw.linenoise);
 	caRed->setDefault( defParams->raw.cared);
 	caBlue->setDefault( defParams->raw.cablue);
+	exPos->setDefault( defParams->raw.expos);
+	exPreser->setDefault( defParams->raw.preser);
+	
 	greenEqThreshold->setDefault (defParams->raw.greenthresh);
 	if (pedited) {
 		lineDenoise->setDefaultEditedState( pedited->raw.linenoise ? Edited : UnEdited);
 		caRed->setDefaultEditedState( pedited->raw.caRed ? Edited : UnEdited);
 		caBlue->setDefaultEditedState( pedited->raw.caBlue ? Edited : UnEdited);
+		exPos->setDefaultEditedState( pedited->raw.exPos ? Edited : UnEdited);
+		exPreser->setDefaultEditedState( pedited->raw.exPreser ? Edited : UnEdited);
+		
 		greenEqThreshold->setDefaultEditedState(pedited->raw.greenEq ? Edited : UnEdited);
 	}else{
 		lineDenoise->setDefaultEditedState( Irrelevant );
 		caRed->setDefaultEditedState( Irrelevant );
 		caBlue->setDefaultEditedState( Irrelevant );
+		exPos->setDefaultEditedState( Irrelevant );
+		exPreser->setDefaultEditedState( Irrelevant );
+		
 		greenEqThreshold->setDefaultEditedState(Irrelevant );
 	}
 }
diff --git a/rtgui/preprocess.h b/rtgui/preprocess.h
index ec699e91f..af8a76244 100644
--- a/rtgui/preprocess.h
+++ b/rtgui/preprocess.h
@@ -37,6 +37,8 @@ class PreProcess : public Gtk::VBox, public AdjusterListener, public ToolPanel{
 
 	Adjuster* caRed;
     Adjuster* caBlue;
+	Adjuster* exPos;
+	Adjuster* exPreser;
     Adjuster* lineDenoise;
     Adjuster* greenEqThreshold;
     Gtk::CheckButton* caAutocorrect;