[Radiance-general] color space and efficacy in color.h

[Christian Fusenig]

Dear all,

 I want to visualize 3D designs of TV-Sets and display them on 
calibrated broadcast class A monitors with EBU phosphors.
Is it possible to tell Radiance not to work with the WHTEFFICACY of 179 
lm/w but  the MAXEFFICACY factor of 683 lm/w?
Furthermore i want to use RGB color space with the 'nominal CRT 
Primaries' which are the same as the EBU phosphor coordinates  in 
'color.h'.
I saw the data in the header file but i dont know how to change it. I 
guess this change will affect other programs like falsecolor to.

Whats the advantage working with 179lm/w anyway?  In every book i see 
the factor of 683 lm/w!

-----
#ifdef  NTSC
#define  CIE_x_r        0.670        /* standard NTSC primaries */
....
#else
#define  CIE_x_r        0.640        /* nominal CRT primaries  = EBU 
color space*/
#define  CIE_y_r        0.330
#define  CIE_x_g        0.290
#define  CIE_y_g        0.600
#define  CIE_x_b        0.150
#define  CIE_y_b        0.060
#define  CIE_x_w        0.3333        /* use true white */
#define  CIE_y_w        0.3333
#endif
-----
Does Radiance use the NTSC color space by default ?

I want to create an octree containing the data of a tungsten light 
source i measured.
My goal is to measure the right illuminance under the lamp. I achieved 
it with this command:

echo "1 0 0 0 0 1" |rtrace -I -h lux_test.oct \
            | rcalc -e 
'$1=179*(0.26510582*$1+0.67010582*$2+0.0647883598*$3)'

But i want to create an octree where i can use this command:
echo "1 0 0 0 0 1" |rtrace -I -h lux_test.oct \
            | rcalc -e '$1=683*(0.299*$1+0.587*$2+0.114*$3)'
These factors are the EBU equivalents for brightness in the Y channel.

I hope i made myself understandable, its critical that i can measure the 
correct colors and the correct brightness in Radiance to make sure the 
display will show the exact colors of the design!
Thanks for help so far,

Christian



-- 
Christian Fusenig
Diplomand, Medientechnik
Undergraduate, Media Technology
Hamburg University Of Applied Sciences
http://www.mt.haw-hamburg.de

address: Beim Schlump 27/07
              20144 Hamburg

email:    christian_fusenig at gmx.de

mobile:  ++49 179 5975845