Gimp / Photoshop need help

pauldtv

I have 240 photos that have been scanned as 16bit greyscale, I need them to be 8 bit. I use Gimp at the moment, on a mac, and the process to convert each photo is a bit labour intensive for me. I can't seem to find a way of setting up a macro in Gimp to do this conversion or a way to do a batch process. Is it possible in Gimp? Do I really need to bite the bullet and buy Photoshop, or is there another way to do this?

stcstc

there is a shareware app called graphicconvertor that could do it

Slav

If you don't mind doing it from the command line you can use open source ImageMagick. Get it from http://www.imagemagick.org then go to the directory with you 16-bit images and run this (assuming your images have .tif extension):

for i in ./*.tif ; do convert $i -depth 8 $(basename $i .tif)_8bit.tif ; done

This will simply convert all images from 16 to 8 bit. If you need to pre-process them in 16 bit depth prior to conversion to 8-bit (like doing auto-levels, applying a curve, etc.) then you might want to use some of imagemagick scripts from here: http://www.fmwconcepts.com/imagemagick/index.php

pauldtv

Thank you both.