materials and texfunc

Hi all:

I have some questions.

(1) Besides measure, through which methods I can find the common values of
material property, such as RBG, reflectivity and roughness value? I know
two places: Colar picker at http://luxal.eu/resources/radiance/index.shtml
and Ecotect which provides some examples, but RBG values are not 0-1, should
I divide the RBG value by 255?

(2) When typing "man texfunc", I can not find the command. Is that my
installation problem? I use ubuntu and Radiance version 4.0.

(3) Is that right I can add texture and pattern by using procedural
functions (e.g. wrinkle.cal) and bitmaps accoring to
http://www.artifice.com/radiance/rad_materials.html ? If I have an image
with an .png extension, how can I add the image as the the pattern ?

Thank you.

Jia