CL-Photo is a Common Lisp package for calculation functions used in photography. CL-Photo is written and Copyright © 2005 by Kevin Rosenberg.
The home page for CL-Photo is http://files.kpe.io/cl-photo.
The easiest way to install CL-Photo is to use the Debian GNU/Linux operating system. You can then use the command apt-get install cl-photo to automatically download and install the CL-Photo package.
On a non-Debian system, you need to have ASDF installed to load the system definition file. You will need to change the source pathname in the system file to match the location where you have installed CL-Photo.
Currently, there is no documentation on the functions provided by CL-Photo. However, the source code is instructive.