diff --git a/OCRmyPDF.sh b/OCRmyPDF.sh
index 71a6d3e8..dc331b8e 100644
--- a/OCRmyPDF.sh
+++ b/OCRmyPDF.sh
@@ -6,6 +6,8 @@
 TOOLNAME="OCRmyPDF"
 VERSION="v1.0-rc2"
 
+START=`date +%s`
+
 usage() {
 	cat << EOF
 --------------------------------------------------------------------------------------
@@ -150,11 +152,12 @@ cd "`dirname $0`"
 today=$(date +"%Y%m%d_%H%M")
 fld=$(basename "$FILE_INPUT_PDF" | sed 's/[.][^.]*//')
 TMP_FLD="./tmp/$today.filename.$fld"
+FILE_TMP="$TMP_FLD/tmp.txt"						# temporary file with a very short life used for several things)
 FILE_SIZE_PAGES="$TMP_FLD/page-sizes.txt"				# size in pt of the respective page of the input PDF file
 FILES_OCRed_PDFS="${TMP_FLD}/*-ocred.pdf"				# string matching all 1 page PDF files that need to be merged
 FILE_OUTPUT_PDF_CAT="${TMP_FLD}/ocred.pdf"				# concatenated OCRed PDF files
 FILE_OUTPUT_PDFA_WO_META="${TMP_FLD}/ocred-pdfa-wo-metadata.pdf"	# PDFA file before appending metadata
-FILE_VALIDATION_LOG="${TMP_FLD}/pdf_validation.log"	# log file containing the results of the validation of the PDF/A file
+FILE_VALIDATION_LOG="${TMP_FLD}/pdf_validation.log"			# log file containing the results of the validation of the PDF/A file
 
 # Create tmp folder
 [ $VERBOSITY -ge $LOG_DEBUG ] && echo "Creating temporary folder: \"$TMP_FLD\""
@@ -168,22 +171,21 @@ mkdir -p "${TMP_FLD}"
 [ $VERBOSITY -ge $LOG_DEBUG ] && echo "Input file: Extracting size of each page (in pt)"
 ! identify -format "%w %h\n" "$FILE_INPUT_PDF" > "$FILE_SIZE_PAGES" \
 	&& echo "Could not get size of PDF pages. Exiting..." >&2 && exit $EXIT_BAD_INPUT_FILE
-sed -I "" '/^$/d' "$FILE_SIZE_PAGES"	# removing empty lines (last one should be)
+sed -i "" '/^$/d' "$FILE_SIZE_PAGES"	# removing empty lines (last one should be)
 numpages=`cat "$FILE_SIZE_PAGES" | wc -l | sed 's/^ *//g'`
-[ $VERBOSITY -ge $LOG_INFO ] && echo "Input file: The file has $numpages pages"
+numpages=`printf "%04d" $numpages`	# add leading zeros to the page number
 
 # Itterate the pages of the input pdf file
 cpt="1"
 while read pageSize ; do
 
-	# add leading zeros to the page number
-	page=`printf "%04d" $cpt`
-	[ $VERBOSITY -ge $LOG_INFO ] && echo "Processing page $page"
+	page=`printf "%04d" $cpt`	# add leading zeros to the page number
+	[ $VERBOSITY -ge $LOG_INFO ] && echo "Processing page $page / $numpages"
 	
 	# create the name of the required file
 	curOrigImg="$TMP_FLD/${page}_Image"			# original image available in the current PDF page 
-							# (the image file may have a different orientation than in the pdf file)
-	curHocr="$TMP_FLD/$page.hocr"			# hocr file to be generated by the OCR SW for the current page
+								# (the image file may have a different orientation than in the pdf file)
+	curHocr="$TMP_FLD/$page.hocr"				# hocr file to be generated by the OCR SW for the current page
 	curOCRedPDF="$TMP_FLD/${page}-ocred.pdf"		# PDF file containing the image + the OCRed text for the current page
 	curOCRedPDFDebug="$TMP_FLD/${page}-debug-ocred.pdf"	# PDF file containing data required to find out if OCR worked correctly
 	
@@ -193,7 +195,7 @@ while read pageSize ; do
 	[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: size ${heightPDF}x${widthPDF} (h*w in pt)"
 	# extract raw image from pdf file to compute resolution
 	# unfortunatelly this image can have another orientation than in the pdf...
-	# so we will have to extract it again later
+	# so we will have to extract it again later using pdftoppm
 	pdfimages -f $page -l $page -j "$FILE_INPUT_PDF" "$curOrigImg" 1>&2	
 	# count number of extracted images
 	nbImg=`ls -1 "$curOrigImg"* | wc -l`
@@ -215,10 +217,17 @@ while read pageSize ; do
 	fi
 	[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Page $page: size ${heightCurImg}x${widthCurImg} (h*w pixel)"	
 	# compute the resolution of the image
-	dpi_x=$(($widthCurImg*72/$widthPDF))
-	dpi_y=$(($heightCurImg*72/$heightPDF))
-	[ "$dpi_x" -ne "$dpi_y" ] && echo "X/Y resolutions not equal ($dpi_x/$dpi_y). Exiting..." >&2 && exit $EXIT_BAD_INPUT_FILE
-	dpi="$dpi_x"
+	dpi_x=`echo "scale=5;$widthCurImg*72/$widthPDF" | bc`
+	dpi_y=`echo "scale=5;$heightCurImg*72/$heightPDF" | bc`
+	# compute the maximum allowed resolution difference that can be cause by:
+	# - the truncated PDF with/height in pt
+	# - the precision of dpi value
+	epsilon=`echo "scale=5;($widthCurImg*72/$widthPDF^2)+($heightCurImg*72/$heightPDF^2)+0.00002" | bc`	# max inaccuracy due to truncation of PDF size in pt
+	diff1=`echo "($dpi_x - $dpi_y) < $epsilon " | bc`
+	diff2=`echo "($dpi_y - $dpi_x) < $epsilon " | bc`
+	[ $diff1 -eq 0 -o $diff2 -eq 0 ] && echo "Resolutions difference ($dpi_x/$dpi_y) higher than expected ($epsilon). Exiting..." >&2 && exit $EXIT_BAD_INPUT_FILE
+	dpi=`echo "scale=5;($dpi_x+$dpi_y)/2+0.5" | bc` # adding 0.5 is required for rounding
+	dpi=`echo "scale=0;$dpi/1" | bc`		# round to the nearest integer
 	
 	# Identify if page image should be saved as ppm (color) or pgm (gray)
 	ext="ppm"
@@ -333,7 +342,7 @@ EOF
 [ $VERBOSITY -ge $LOG_DEBUG ] && echo "Output file: Checking compliance to PDF/A standard" 
 java -jar "$JHOVE" -c "$JHOVE_CFG" -m PDF-hul "$FILE_OUTPUT_PDFA" > "$FILE_VALIDATION_LOG"
 grep -i "Status|Message" "$FILE_VALIDATION_LOG" # summary of the validation
-[ $VERBOSITY -ge $LOG_DEBUG ] && cat "$FILE_VALIDATION_LOG"
+[ $VERBOSITY -ge $LOG_DEBUG ] && echo "The full validation log is available here: \"$FILE_VALIDATION_LOG\""
 # check the validation results
 pdf_valid=1
 grep -i 'ErrorMessage' "$FILE_VALIDATION_LOG" >&2 && pdf_valid=0
@@ -353,5 +362,8 @@ if [ $KEEP_TMP -eq 0 ]; then
 fi
 
 
+END=`date +%s`
+[ $VERBOSITY -ge $LOG_DEBUG ] && echo "Script took $(($END-$START)) seconds"
+
 
 [ $pdf_valid -ne 1 ] && exit $EXIT_INVALID_OUPUT_PDFA || exit 0