Deletes known watermark

convert.sh

#!/bin/bash

MASK="mask.png"
NEGATE_FIXED="negate_fixed.png"
NEGATE="negate.png"
#convert -density 300 -trim test.pdf -quality 100 -flatten -sharpen 0x1.0 test.jpg
convert $MASK -negate $MASK
for i in *.png
do
    convert $i -negate $NEGATE
    convert $NEGATE $MASK -compose difference -composite $NEGATE_FIXED
    convert $NEGATE_FIXED -negate $i
done
rm $NEGATE $NEGATE_FIXED
mkdir files
mv $MASK ./files
#convert *.png result.pdf

#for a in [0-9]*.png; do
#    mv $a ./new/`printf %04d.%s ${a%.*} ${a##*.}`
#done