[Radiance-general] accurate light levels

[william reynolds]

hi there

As I said in my other question today (spliting a render by light 
sources) I am quite new to radiance, and I am having some issues setting 
  up my renderings. I have radiance installed and working fine, but I 
dont quite understand how I make sure the brightness of the final render 
is realistic. There are a few reasons for this:

I'm not sure what exposure setting to use with pfilt - is it as simple 
as setting '-e 1' so as not to adjust the exposure? I have tried this 
and my images all come out very dark, but this might be because I don't 
have enough light in the scene (see next paragraph, below).

Has anyone used radiance with any theatrical light fixtures? and would 
they be prepared to share the .rad files for them? I have found the .rad 
descriptions of architectural fixtures, but i'm not familiar with any of 
them, and even if I was I need to be able to use accurate models of the 
specific instruments I'll be using in theatres. I would simply build my 
own files, using the iestorad utility, but rather unhelpfully the 
instrument manufacturers dont seem willing to give out ies data.

Has anyone made any more materials information available to the public? 
I have looked through the material.rad list of materilas in the lib 
folder, but I'm specifically looking black paint and heavy black cloth 
type materials. If not, then does anyone have any recomendations of how 
to go about determining good values to use in my own materials 
definitions? I dont have access to any way of measuring reflected light 
levels in an experiment.

Thanks for your help with my probably rather basic questions
Will