diff --git a/stretchtoolbar.cpp b/stretchtoolbar.cpp
index 1a52804..a4b6711 100644
--- a/stretchtoolbar.cpp
+++ b/stretchtoolbar.cpp
@@ -114,18 +114,21 @@ void StretchToolbar::stretchImage(Image *img)
         float max2 = 0;
         for(; i < ch; i++)
         {
-            double median, mad;
+            double median, mad, max;
             median = stats.m_median[i];
             mad = stats.m_mad[i];
+            max = stats.m_max[i];
             median /= img->rawImage()->norm();
             mad /= img->rawImage()->norm();
+            max /= img->rawImage()->norm();
             float bp = median + mad * BLACK_POINT_SIGMA * MAD_TO_SIGMA;
             float mid = MTF(median - bp, TARGET_BACKGROUND);
             m_mtfParam.blackPoint[i-o] = bp;
-            m_mtfParam.midPoint[i-o] = mid;
-            m_mtfParam.whitePoint[i-o] = 1.0f;
+            m_mtfParam.midPoint[i-o] = mid / max;
+            m_mtfParam.whitePoint[i-o] = max;
             bp2 += bp;
             mid2 += mid;
+            max2 = max > max2 ? max : max2;
         }
         if(ch == 1)
         {
@@ -137,7 +140,7 @@ void StretchToolbar::stretchImage(Image *img)
         {
             m_mtfParam.blackPoint[0] = m_mtfParam.blackPoint[1] = m_mtfParam.blackPoint[2] = bp2 / ch;
             m_mtfParam.midPoint[0] = m_mtfParam.midPoint[1] = m_mtfParam.midPoint[2] = mid2 / ch;
-            m_mtfParam.whitePoint[0] = m_mtfParam.whitePoint[1] = m_mtfParam.whitePoint[2] = 1.0f;
+            m_mtfParam.whitePoint[0] = m_mtfParam.whitePoint[1] = m_mtfParam.whitePoint[2] = max2;
             m_stfSlider->setMTFParams(m_mtfParam.blackPoint[0], m_mtfParam.midPoint[0], m_mtfParam.whitePoint[0]);
         }
         else