Images are to print on Digital and Offset machines. So final output has to be 300dpi PDF.
-
Images resolution = 12 * 300 X 36 * 300. That means 3600 X 10800 pixels. This will be maximum size restricted. So we don't need to bother about more heavy image.
-
Split into half means divide 12in x 36in to two 12in x 18in images and save separately.