diff --git a/rtengine/rcd_demosaic.cc b/rtengine/rcd_demosaic.cc
index b12ce1473..3a88e1a9a 100644
--- a/rtengine/rcd_demosaic.cc
+++ b/rtengine/rcd_demosaic.cc
@@ -79,7 +79,7 @@ void RawImageSource::rcd_demosaic(size_t chunkSize, bool measure)
     
     const unsigned int cfarray[2][2] = {{FC(0,0), FC(0,1)}, {FC(1,0), FC(1,1)}};
     constexpr int tileBorder = 9; // avoid tile-overlap errors
-    constexpr int rcdBorder = 6;  // for the outermost tiles we can have a smaller outer border
+    constexpr int rcdBorder = 9;
     constexpr int tileSize = 194;
     constexpr int tileSizeN = tileSize - 2 * tileBorder;
     const int numTh = H / (tileSizeN) + ((H % (tileSizeN)) ? 1 : 0);