p/graphic exposure and whitepoint settings?

[Dave Buckley]

i have been doing background reading on the above subject.

 

it is all well and good being able to do something in 3d, but i want to understand why.

 

when lighting an interior/exterior, daytime/nightime, how do you know what value to set your whitepoint at on the p/graphic exposure.

 

from what i gather, in an daylight interior, the main light source would be the daylight coming through the window, therefore to get realistic results, we should set the whitepoint on the exposure controls to a similar kelvin temperature as the sun daylight would have at that time of day.

 

so for example, it is midday in june so the daylight system would have a kelvin value of around 5500k, i also have some IES lights with a kelvin temp of 3600k on the interior. if it is the interior i am rendering, then am i right in saying that the whitepoint value on my exposure should be set to around 5500k in order to get realistic results, as although i have interior lights turned on, the daylight system is still the dominant light source.

 

however, if i render the same scene but at 9pm, my whitepoint should be set to 3600k as my interior lights have now become the dominant source because the sun is now non existent.

 

could people give me there thoughts on this and also tell me if i have got the idea or if i am missing something

 

kind regards

[pixelperfectg]

when lighting an interior/exterior, daytime/nightime, how do you know what value to set your whitepoint at on the p/graphic exposure.

I'm not sure if there's a rule of thumb for this in the world of photography or not. But for CG I think it's just whatever looks right to you. Thankfully it's far easier for us (CG artists) to balance our white point/kelvin settings than in the real world.

 

For reference my digital camera has these presets:

Daylight = 5200k

Shade = 7000k

Cloudy = 6000k

Tungsten = 3200k

White Fluorescent light = 4000k

AWB (auto)

Flash

Custom

 

Here's my random thoughts on scenario specific kelvin settings:

 

If I were to photograph (or render) an arch-exterior at night, I'd use a daylight preset because I like the color combination of the warm yellow/orange interior lighting against the cold blue/purple evening sky.

 

If I were to photograph (or render) an arch-interior at night, I'd probably use the tungsten preset (or in that range) to eliminate some or all of the harsh orange/yellow tint.

 

If I were to photograph (or render) an arch-interior with multiple light sources such as fluorescent, tungsten and even sunlight/daylight...well, I'd probably have to fiddle around a while with the white balance settings to find a happy medium. Perhaps others that have more experience with photography will chime in with a better method for this scenario.