diff --git a/rtengine/ipsharpen.cc b/rtengine/ipsharpen.cc
index 505dd5db9..3c455b03e 100644
--- a/rtengine/ipsharpen.cc
+++ b/rtengine/ipsharpen.cc
@@ -122,6 +122,9 @@ void ImProcFunctions::deconvsharpening (float** luminance, float** tmp, int W, i
             if (!needdamp) {
                 // apply gaussian blur and divide luminance by result of gaussian blur
                 gaussianBlur (tmpI, tmp, W, H, sigma, nullptr, GAUSS_DIV, luminance);
+#ifdef _OPENMP
+                #pragma omp for
+#endif
                 for (int i = 0; i < H; i++) {
                     for(int j = 0; j < W; j++) {
                         tmp[i][j] = max(tmp[i][j], 0.f);