diff --git a/api/baseapi.cpp b/api/baseapi.cpp
index b24742435f..d9bc1f9d9a 100644
--- a/api/baseapi.cpp
+++ b/api/baseapi.cpp
@@ -2223,6 +2223,8 @@ void TessBaseAPI::Threshold(Pix** pix) {
   if (y_res < kMinCredibleResolution || y_res > kMaxCredibleResolution) {
     // Use the minimum default resolution, as it is safer to under-estimate
     // than over-estimate resolution.
+    tprintf("Warning. Invalid resolution %d dpi. Using %d instead.\n",
+            y_res, kMinCredibleResolution);
     thresholder_->SetSourceYResolution(kMinCredibleResolution);
   }
   PageSegMode pageseg_mode =
diff --git a/ccmain/osdetect.cpp b/ccmain/osdetect.cpp
index f2fe94a1c3..69e626222f 100644
--- a/ccmain/osdetect.cpp
+++ b/ccmain/osdetect.cpp
@@ -164,8 +164,14 @@ void remove_nontext_regions(tesseract::Tesseract *tess, BLOCK_LIST *blocks,
   int vertical_y = 1;
   tesseract::TabVector_LIST v_lines;
   tesseract::TabVector_LIST h_lines;
-  int resolution = (kMinCredibleResolution > pixGetXRes(pix)) ?
-      kMinCredibleResolution : pixGetXRes(pix);
+  int resolution;
+  if (kMinCredibleResolution > pixGetXRes(pix)) {
+    resolution = kMinCredibleResolution;
+    tprintf("Warning. Invalid resolution %d dpi. Using %d instead.\n",
+            pixGetXRes(pix), resolution);
+  } else {
+    resolution = pixGetXRes(pix);
+  }
 
   tesseract::LineFinder::FindAndRemoveLines(resolution, false, pix,
                                             &vertical_x, &vertical_y,