diff --git a/services/surfaceflinger/Effects/Daltonizer.cpp b/services/surfaceflinger/Effects/Daltonizer.cpp
index a7090c5..65f2605 100644
--- a/services/surfaceflinger/Effects/Daltonizer.cpp
+++ b/services/surfaceflinger/Effects/Daltonizer.cpp
@@ -37,6 +37,18 @@
     }
 }
 
+void Daltonizer::setLevel(int32_t level) {
+    if (level < 0 || level > 10) {
+        return;
+    }
+
+    float newLevel = level / 10.0f;
+    if (std::fabs(mLevel - newLevel) > 0.09f) {
+        mDirty = true;
+    }
+    mLevel = newLevel;
+}
+
 const mat4& Daltonizer::operator()() {
     if (mDirty) {
         mDirty = false;
@@ -117,25 +129,24 @@
     // a color blind user and "spread" this error onto the healthy cones.
     // The matrices below perform this last step and have been chosen arbitrarily.
 
-    // The amount of correction can be adjusted here.
-
+    // Scale 0 represents no change (mColorTransform is identical matrix).
     // error spread for protanopia
-    const mat4 errp(    1.0, 0.7, 0.7, 0,
-                        0.0, 1.0, 0.0, 0,
-                        0.0, 0.0, 1.0, 0,
-                          0,   0,   0, 1);
+    const mat4 errp(1.0, mLevel, mLevel, 0.0,
+                    0.0,    1.0,    0.0, 0.0,
+                    0.0,    0.0,    1.0, 0.0,
+                    0.0,    0.0,    0.0, 1.0);
 
     // error spread for deuteranopia
-    const mat4 errd(    1.0, 0.0, 0.0, 0,
-                        0.7, 1.0, 0.7, 0,
-                        0.0, 0.0, 1.0, 0,
-                          0,   0,   0, 1);
+    const mat4 errd(   1.0, 0.0,    0.0, 0.0,
+                    mLevel, 1.0, mLevel, 0.0,
+                       0.0, 0.0,    1.0, 0.0,
+                       0.0, 0.0,    0.0, 1.0);
 
     // error spread for tritanopia
-    const mat4 errt(    1.0, 0.0, 0.0, 0,
-                        0.0, 1.0, 0.0, 0,
-                        0.7, 0.7, 1.0, 0,
-                          0,   0,   0, 1);
+    const mat4 errt(   1.0,    0.0, 0.0, 0.0,
+                       0.0,    1.0, 0.0, 0.0,
+                    mLevel, mLevel, 1.0, 0.0,
+                       0.0,    0.0, 0.0, 1.0);
 
     // And the magic happens here...
     // We construct the matrix that will perform the whole correction.
diff --git a/services/surfaceflinger/Effects/Daltonizer.h b/services/surfaceflinger/Effects/Daltonizer.h
index 2fb60e9..f5eaae7 100644
--- a/services/surfaceflinger/Effects/Daltonizer.h
+++ b/services/surfaceflinger/Effects/Daltonizer.h
@@ -21,6 +21,9 @@
 
 namespace android {
 
+// Forward declare test class
+class DaltonizerTest;
+
 enum class ColorBlindnessType {
     None,               // Disables the Daltonizer
     Protanomaly,        // L (red) cone deficient
@@ -37,10 +40,15 @@
 public:
     void setType(ColorBlindnessType type);
     void setMode(ColorBlindnessMode mode);
+    // sets level for correction saturation, [0-10].
+    void setLevel(int32_t level);
 
     // returns the color transform to apply in the shader
     const mat4& operator()();
 
+    // For testing.
+    friend class DaltonizerTest;
+
 private:
     void update();
 
@@ -48,6 +56,8 @@
     ColorBlindnessMode mMode = ColorBlindnessMode::Simulation;
     bool mDirty = true;
     mat4 mColorTransform;
+    // level of error spreading, [0.0-1.0].
+    float mLevel = 0.7f;
 };
 
 } /* namespace android */