diff --git a/CamScanner.cs b/CamScanner.cs
index cce66e9..2d0b19c 100644
--- a/CamScanner.cs
+++ b/CamScanner.cs
@@ -374,28 +374,6 @@ public static class DocumentScanner
             }
         }
 
-        // 墨迹映射
-        for (int i = 0; i < grayData.Length; i++)
-        {
-            int ink = bgData[i] - grayData[i];
-            if (ink < 0) ink = 0;
-
-            double inkNorm = (double)ink / ink95;
-            if (inkNorm > 1.0) inkNorm = 1.0;
-
-            double darkness = Math.Pow(inkNorm, 0.45);
-
-            int val = (int)(255.0 * (1.0 - darkness));
-            if (val < 0) val = 0;
-            if (val > 255) val = 255;
-            resultData[i] = (byte)val;
-        }
-
-        // --- 阴影修复：从边缘向内扫描，把连续暗像素区域设为白色 ---
-        // 阴影只出现在文档四周边缘（拍照翘边/光照不均）
-        // 从上下左右四个方向向内扫描原始灰度，遇到连续暗区域就标记为阴影
-        byte[] shadowFlag = new byte[w * h]; // 0=正常, 1=阴影
-
         // 计算"正常纸面亮度"：取灰度图中心区域的均值
         int cx1 = w / 4;
         int cx2 = w * 3 / 4;
@@ -412,11 +390,45 @@ public static class DocumentScanner
             }
         }
         int paperBright = (int)(centerSum / Math.Max(centerCount, 1));
-        // 阴影判定：原始灰度低于纸面亮度的55%
-        int darkThresh = (int)(paperBright * 0.55);
 
-        // 从四个边缘向内扫描
-        int maxScanDepth = Math.Max(w, h) / 8; // 最多扫描图像尺寸的1/8
+        // 墨迹映射（带阴影/折痕保护）
+        // 文字特征：背景亮（接近paperBright），gray比背景低 → ink大
+        // 折痕/阴影特征：gray本身就暗，背景估计也被拉低 → ink也可能大
+        // 区分方法：看背景估计值是否接近正常纸面亮度
+        //   如果 bgData[i] 接近 paperBright → 正常文字区域，正常处理
+        //   如果 bgData[i] 远低于 paperBright → 阴影/折痕区域，抑制墨迹深度
+        double bgThreshRatio = 0.75; // 背景低于纸面亮度75%就开始抑制
+
+        for (int i = 0; i < grayData.Length; i++)
+        {
+            int ink = bgData[i] - grayData[i];
+            if (ink < 0) ink = 0;
+
+            double inkNorm = (double)ink / ink95;
+            if (inkNorm > 1.0) inkNorm = 1.0;
+
+            double darkness = Math.Pow(inkNorm, 0.45);
+
+            // 阴影/折痕抑制：背景越暗，墨迹输出越浅
+            double bgRatio = (double)bgData[i] / Math.Max(paperBright, 1);
+            if (bgRatio < bgThreshRatio)
+            {
+                // 背景很暗 → 阴影区域，大幅抑制
+                // 线性衰减：bgRatio从0.75→0时，darkness从原值→0
+                double suppress = bgRatio / bgThreshRatio;
+                darkness = darkness * suppress * suppress; // 平方衰减，更激进
+            }
+
+            int val = (int)(255.0 * (1.0 - darkness));
+            if (val < 0) val = 0;
+            if (val > 255) val = 255;
+            resultData[i] = (byte)val;
+        }
+
+        // --- 边缘阴影修复：从边缘向内扫描连续暗像素 ---
+        byte[] shadowFlag = new byte[w * h];
+        int darkThresh = (int)(paperBright * 0.55);
+        int maxScanDepth = Math.Max(w, h) / 8;
 
         // 上边缘
         for (int x = 0; x < w; x++)