diff --git a/lib/GfxRenderer/BitmapHelpers.cpp b/lib/GfxRenderer/BitmapHelpers.cpp
index e9dbb64d..07e985f3 100644
--- a/lib/GfxRenderer/BitmapHelpers.cpp
+++ b/lib/GfxRenderer/BitmapHelpers.cpp
@@ -52,14 +52,13 @@ int adjustPixel(int gray) {
 
   return gray;
 }
-// Simple quantization without dithering - divide into 4 levels
-// The thresholds are fine-tuned to the X4 display
+// Simple quantization without dithering — evenly-spaced midpoint thresholds for factory LUT
 uint8_t quantizeSimple(int gray) {
-  if (gray < 45) {
+  if (gray < 43) {
     return 0;
-  } else if (gray < 70) {
+  } else if (gray < 128) {
     return 1;
-  } else if (gray < 140) {
+  } else if (gray < 213) {
     return 2;
   } else {
     return 3;
diff --git a/lib/GfxRenderer/BitmapHelpers.h b/lib/GfxRenderer/BitmapHelpers.h
index 8f49124c..8220fc22 100644
--- a/lib/GfxRenderer/BitmapHelpers.h
+++ b/lib/GfxRenderer/BitmapHelpers.h
@@ -125,37 +125,21 @@ class AtkinsonDitherer {
     if (adjusted < 0) adjusted = 0;
     if (adjusted > 255) adjusted = 255;
 
-    // Quantize to 4 levels
+    // Quantize to 4 levels — evenly-spaced midpoint thresholds for factory LUT
     uint8_t quantized;
     int quantizedValue;
-    if (false) {  // original thresholds
-      if (adjusted < 43) {
-        quantized = 0;
-        quantizedValue = 0;
-      } else if (adjusted < 128) {
-        quantized = 1;
-        quantizedValue = 85;
-      } else if (adjusted < 213) {
-        quantized = 2;
-        quantizedValue = 170;
-      } else {
-        quantized = 3;
-        quantizedValue = 255;
-      }
-    } else {  // fine-tuned to X4 eink display
-      if (adjusted < 30) {
-        quantized = 0;
-        quantizedValue = 15;
-      } else if (adjusted < 50) {
-        quantized = 1;
-        quantizedValue = 30;
-      } else if (adjusted < 140) {
-        quantized = 2;
-        quantizedValue = 80;
-      } else {
-        quantized = 3;
-        quantizedValue = 210;
-      }
+    if (adjusted < 43) {
+      quantized = 0;
+      quantizedValue = 0;
+    } else if (adjusted < 128) {
+      quantized = 1;
+      quantizedValue = 85;
+    } else if (adjusted < 213) {
+      quantized = 2;
+      quantizedValue = 170;
+    } else {
+      quantized = 3;
+      quantizedValue = 255;
     }
 
     // Calculate error (only distribute 6/8 = 75%)
@@ -229,37 +213,21 @@ class FloydSteinbergDitherer {
     if (adjusted < 0) adjusted = 0;
     if (adjusted > 255) adjusted = 255;
 
-    // Quantize to 4 levels (0, 85, 170, 255)
+    // Quantize to 4 levels — evenly-spaced midpoint thresholds for factory LUT
     uint8_t quantized;
     int quantizedValue;
-    if (false) {  // original thresholds
-      if (adjusted < 43) {
-        quantized = 0;
-        quantizedValue = 0;
-      } else if (adjusted < 128) {
-        quantized = 1;
-        quantizedValue = 85;
-      } else if (adjusted < 213) {
-        quantized = 2;
-        quantizedValue = 170;
-      } else {
-        quantized = 3;
-        quantizedValue = 255;
-      }
-    } else {  // fine-tuned to X4 eink display
-      if (adjusted < 30) {
-        quantized = 0;
-        quantizedValue = 15;
-      } else if (adjusted < 50) {
-        quantized = 1;
-        quantizedValue = 30;
-      } else if (adjusted < 140) {
-        quantized = 2;
-        quantizedValue = 80;
-      } else {
-        quantized = 3;
-        quantizedValue = 210;
-      }
+    if (adjusted < 43) {
+      quantized = 0;
+      quantizedValue = 0;
+    } else if (adjusted < 128) {
+      quantized = 1;
+      quantizedValue = 85;
+    } else if (adjusted < 213) {
+      quantized = 2;
+      quantizedValue = 170;
+    } else {
+      quantized = 3;
+      quantizedValue = 255;
     }
 
     // Calculate error