calculating white balance colour

[mdi]

heres a question.


cameras today are able to calculate the correct WB to use..you can do this by taking a photo of a light gray/white board, and then the camera is able to calculate the correct WB to use based apon the photo taken (pro cameras are able to make a custom WB that falls outside of the 9 or so WB presets)

So would it be posible to set up a phisical camera/vray sun/sky, get the image correctly exposed...and then place a gray board in the scene and from the RBG info gathered from the gray card calculate the correct colour to place in the WB slot of the Vray camera?

obvisoly this could be just done by eye, guessing the colour, or adjusting the "daylight" preset...but i would be intrested to know if theres a way to calculate it like a real phisical camera?

[vlado]

Yep:

1) Set the white balance to white;
2) Render the grey board image;
3) Take the RGB value of a pixel from the grey board image and put this as the RGB values of the white balance color;
4) Now when you render, the grey board will indeed be grey.

Best regards,
Vlado

[mdi]

hahaha, never thought it would be that easy!!!

[^Lele^]

What i do in the exposimeter is exactly similar, only i do it on an average pixel colour.
It may be worth trying to do it with an override material applied, indeed, rather than with the user materials in the scene.
As a side note, i noticed that if i use full saturation colours i get an entirely blue image with color = to 0,0,#ind
A bug or a feature?

[mdi]

What i do in the exposimeter is exactly similar, only i do it on an average pixel colour.
It may be worth trying to do it with an override material applied, indeed, rather than with the user materials in the scene.
As a side note, i noticed that if i use full saturation colours i get an entirely blue image with color = to 0,0,#ind
A bug or a feature?

exposimeter ??

[ene.xis]

http://www.chaosgroup.com/forum/phpB...ic.php?t=20175

[mdi]

http://www.chaosgroup.com/forum/phpBB2/viewtopic.php?t=20175

ohhhhh...he aint half clever !

dl now...cheers for the heads up...and cheers ^Lele^

[ene.xis]

can t really live without all those funky tools nowadays, thanx Lele, again and again!