diff --git a/scan b/scan
index 391388e..fb902aa 100755
--- a/scan
+++ b/scan
@@ -26,7 +26,7 @@ DESKEW=0
 VERBOSE=0
 SKIP_EMPTY_PAGES=0
 
-TMP_DIR=`mktemp -d`
+TMP_DIR=$(mktemp -d)
 trap "rm -rf $TMP_DIR" 0
 
 # Parse command-line options
diff --git a/scan_perpage b/scan_perpage
index e0ec972..c0ac2bc 100755
--- a/scan_perpage
+++ b/scan_perpage
@@ -56,20 +56,24 @@ if [ "$UNPAPER" == "" -o "$SEARCHABLE" == "" -o "$RESOLUTION" == "" -o "$RESOLUT
 fi
 
 IMAGE_PATH=$1
-IMAGE_DIR=`dirname $1`
-IMAGE_FILE=`basename $1`
+IMAGE_DIR=$(dirname $1)
+IMAGE_FILE=$(basename $1)
 
 process_page() {
   log ""
   log "-------------------------------------------------------------------------------"
-  log "Post-processing scanned page ${IMAGE_FILE}, deskew=$UNPAPER, searchable=$SEARCHABLE..."
+  log "Post-processing scanned page ${IMAGE_PATH}, deskew=$UNPAPER, searchable=$SEARCHABLE..."
+
+
+  if [[ $SKIP_EMPTY_PAGES -eq 1 ]]; then
+    PERCENTAGE_WHITE=$(convert "$IMAGE_PATH" -fuzz 0% -negate -threshold 0 -negate -format "%[fx:100*mean]" info:) || PERCENTAGE_WHITE=0
+    log "$IMAGE_PATH has $PERCENTAGE_WHITE % white"
+  else
+    PERCENTAGE_WHITE=0
+  fi
 
-  
-  [[ $SKIP_EMPTY_PAGES -eq 1 ]] && PERCENTAGE_WHITE=`convert "$IMAGE_PATH" -fuzz 0% -negate -threshold 0 -negate -format "%[fx:100*mean]" info:` || PERCENTAGE_WHITE=0
-  log "$IMAGE_PATH has $PERCENTAGE_WHITE % white"
-    
   PP_PREFIX=
-  if (( $(echo "$PERCENTAGE_WHITE < 99.8" |bc -l) )); then
+  if (( $(echo "$PERCENTAGE_WHITE < 99.8" | bc -l) )); then
     if [ $UNPAPER -eq 1 ]; then
       log "Applying unpaper post-processing to image data..."
       PP_PREFIX="unpaper-"
@@ -102,7 +106,7 @@ process_page() {
   else
     log "Skipping empty page $IMAGE_FILE with white percentage $PERCENTAGE_WHITE"
   fi
-  
+
   status=$?
   rm $IMAGE_PATH
   if [ -f $IMAGE_DIR/$PP_PREFIX$IMAGE_FILE ]; then