[Radiance-general] Re: Again transmissivity for color filter/ glass

[Christian Fusenig]

Hey Greg,

>It sounds like we're back on track, here.  I'm relieved.
>  
>
And I AM too!!!

>Did you erase the info. from the CM-2002?  Maybe the spectral data is  
>still there.  It would be better to use it if you have it.  Even if  
>you used a tungsten illuminant to determine the XYZ value, shifting  
>to a different illuminant without the spectral data is a shaky business.
>  
>
I try to retrieve the spectral data.

As i think i understand this procedure, now i am left with my last problem:

I have a plexiglass cylinder with a height of ca. 2 cm  and a radius of 
ca. 15 cm.
I got the transmission/transmissivity of this glass from the 
manufacturer it´s around 92%.

On top and on the side of this cylinder there is this LEE 061 Mist Blue 
color filter attached.
I have the spectrum of this filter.

This cylinder is part of a news desk in a studio and ca. 1 m under this 
glass there is a incandescent spotlight ca. 3200K  that shines at it.
The whole desk is in the same scene described in my previous mail, color 
temperatures vary from 2400 - 3200 K.

I have the problem now that this filter is not attached directly to a 
lamp. If it would be like this i would simply multiply the two spectra 
and convert to CIE xy etc..
Like in 'RwR' p. 435

Now i want to ad the color attributes of this filter somehow to this 
cylinder:
I think the best way to simulate this, is to use the 'trans' material 
because the surface shouldn't be so shiny or polished like the glass 
material.
I made an Excel sheet to calculate the 'trans' parameters but it's 
confusing.

What would you suggest?
(I promise this my last problem ;-)

Thanks again,

Christian