Kooka: Scanning an exact duplicate

[Bruce]

I am trying to figure out how to use Kooka, my scanner and a colour
printer as a colour copier - i.e., to scan and print an exact copy of an
image. I'd like to scan, save, and print out a copy that is the exact same
size as the original (basically, I want to copy some photos, without
scaling).

This doesn't seem to be very easy. The only way I can figure out how to do
this is

a) scan and save the image
b) open it in the Gimp
c) get out a ruler and measure the original
d) scale the scanned image to the size of the original
e) print

Which sort of works, but adds the potential for human error and an
inexactness that I would rather avoid.

Is there an easier and more foolproof way to do this?

B.