#split images in half to recover original book pages
#for i in `ls *.jpg`; do convert $i -crop 50%x100% +repage horizontal/"${i%.jpg}"_%d.jpg ; done; cd horizontal

for i in `ls *jpg`; do convert $i ${i%jpg}pnm ; done
for i in `ls *pnm`; do pnmtops $i -nocenter -equalpixels -dpi 60 > ${i%pnm}ps ; done
#collate ps files
gs -sDEVICE=pdfwrite -sOutputFile=myfile.pdf -dNOPAUSE -f *ps -c quit
pdf2ps myfile.pdf myfile.ps

#reorder pages for bookbinding and duplex printing
psbook -s4 myfile.ps myfile_book.ps
psnup  -2 myfile_book.ps myfile_booklet.ps
gs -sDEVICE=pdfwrite -sOutputFile=myfile_booklet.pdf -dNOPAUSE -f myfile_booklet.ps -c quit
#print in chrome or whatever
#when printing on laserjet 1012 place paper in paper tray white side up; do not rotate paper