diff --git a/ETA.py b/ETA.py
index 234b21c..3274a10 100644
--- a/ETA.py
+++ b/ETA.py
@@ -381,45 +381,103 @@ else:
             cache[ 'calibrations']  = calibrations
             cache[ 'stripes' ]      = stripes
 
+size = border[ 'x' ][ 'max' ] - border[ 'x' ][ 'min' ]
+size_x = size
+size_y =  calibrations[ 'down' ][ 'y' ][ 'min' ] - calibrations[ 'top' ][ 'y' ][ 'max' ]
+
 # Calibration
 
 if calibration != None:
     import wavelength_calibration as wave_calib
-    peaks_calib   = np.loadtxt( calibration ) # sorted list
+    peaks_calib = np.loadtxt( calibration ) # sorted list
     peaks_calib = np.sort( peaks_calib )
-    mean_up = np.mean( data[
+    mean_up   = np.mean( data[
         calibrations[ 'top' ][ 'y' ][ 'min' ] : calibrations[ 'top' ][ 'y' ][ 'max' ],
         calibrations[ 'top' ][ 'x' ][ 'min' ] : calibrations[ 'top' ][ 'x' ][ 'max' ]
     ] , axis = 0 )
-    peaks_up      = np.array(
+    mean_down = np.mean( data[
+        calibrations[ 'down' ][ 'y' ][ 'min' ] : calibrations[ 'down' ][ 'y' ][ 'max' ],
+        calibrations[ 'down' ][ 'x' ][ 'min' ] : calibrations[ 'down' ][ 'x' ][ 'max' ]
+    ] , axis = 0 )
+    peaks_up   = np.array(
         utils.retrieve_peaks(
             mean_up            ,
             window_size = 1    ,
             max_window_size = 1,
         )
     ).astype( int )
+    peaks_down = np.array(
+        utils.retrieve_peaks(
+            mean_down          ,
+            window_size = 1    ,
+            max_window_size = 1,
+        )
+    ).astype( int )
 
-    peakless_up = wave_calib.remove_peaks( mean_up , peaks_up )
+    peakless_up   = wave_calib.remove_peaks( mean_up   , peaks_up   )
+    peakless_down = wave_calib.remove_peaks( mean_down , peaks_down )
     calib = { # hard-coded for now
         'first': 3 ,
-        'last':  20,
+        'last' : 20,
     }
     first , last = wave_calib.get_extremities( peakless_up , peaks_up )
     up    = {
         'first': first,
         'last' : last ,
     }
+    first , last = wave_calib.get_extremities( peakless_down , peaks_down )
+    down  = {
+        'first': first,
+        'last' : last ,
+    }
     peaks_up    = peaks_up[    up[ 'first' ]    : up[ 'last' ]    + 1 ]
+    peaks_down  = peaks_down[  down[ 'first' ]  : down[ 'last' ]  + 1 ]
     peaks_calib = peaks_calib[ calib[ 'first' ] : calib[ 'last' ] + 1 ]
 
-    peaks_up = wave_calib.only_keep_calib( peaks_up , peaks_calib )
+    peaks_up   = wave_calib.only_keep_calib( peaks_up   , peaks_calib )
+    peaks_down = wave_calib.only_keep_calib( peaks_down , peaks_calib )
+
+    diff = peaks_up - peaks_down
+    polyval_vert = np.polyfit( # give diff by horizontal pixel
+        peaks_up,
+        diff    ,
+        3       ,
+    )
+
+    def diff_calc( x , list_y ):
+        """
+        give "good" x list for a given x and y
+        x = 0 start from border[ 'x' ][ 'min' ]
+        y = 0 start from calibrations[ 'top' ][ 'y' ][ 'max' ]
+        """
+        y_top  = 0
+        y_bot  = size_y
+
+        x_top = x
+        x_bot = x + np.polyval( polyval_vert , x )
+
+        a = ( x_top - x_bot ) / ( y_top - y_bot )
+        b = ( 1 / 2 ) * ( x_top + x_bot - a * ( y_top + y_bot ) )
+
+        return ( a * list_y + b ).astype( int )
+
+    new_data = np.zeros( ( size_y , size_x - 199 ) )
+    list_y    = np.arange( 0 , size_y , 1 )
+    for x in range( 100 , size_x - 100 ):
+        diff = diff_calc( x , list_y )
+        cons_diff , i = utils.same_value( diff ) , 0
+        for list_same in cons_diff:
+            new_data[ i : i + len( list_same ) , x - 100 ] = data[
+                calibrations[ 'top' ][ 'y' ][ 'max' ] + i : calibrations[ 'top' ][ 'y' ][ 'max' ] + i + len( list_same ),
+                calibrations[ 'top' ][ 'x' ][ 'min' ] + list_same[0]
+            ]
+            i += len( list_same )
 
     polyval_wavelength = np.polyfit( # x = 0 begins at the start of
-        peaks_up   ,                 # calibartions[ 'top' ][ 'x' ][ 'min' ]
+        peaks_up   ,                 # calibrations[ 'top' ][ 'x' ][ 'min' ]
         peaks_calib,
         1          ,
     )
-
     wavelength = np.polyval(
         polyval_wavelength,
         np.arange(
@@ -429,16 +487,6 @@ if calibration != None:
         )
     )
 
-    plt.plot(
-        peaks_up,
-        peaks_calib - np.polyval(
-            polyval_wavelength,
-            peaks_up          ,
-        )       ,
-    )
-    plt.show()
-    exit()
-
 # First deformation
 
 list_ = data[