-To build, just `make' it. You will need GNU make; it probably won't work
-with any other kind of make(1). The executable is called project1. It
-will produce no output except for the image files scene.ppm and scene.bmp.
+To build, just `make' it. You will need GNU make; it won't work well with
+any other kind of make(1). Once built, the executable is called raytrace.
+
+Caveats:
+
+1. The PPM importer doesn't handle comments, and the BMP importer is also
+quite picky about the depth and color space.