Moonlight Color Temperature

[Vivek Venkatraman]

Well it was a one take and I did not vary the light positions so yes I did get roughly the same sort of look throughout

[Ruth Vilas]

On 11/1/2015 at 1:04 PM, David Mullen ASC said:

If the only light in the scene is moonlight, just use a daylight source like daylight Kinos and dial in a degree of color temp on the camera that gets you the shade of blue you want. Start at 3200K for a traditional "full blue" moonlight and if you want less blue, use something like 4000K or higher.

 

If you have to mix the blue moonlight with warmer tungsten sources in the room and uncorrected daylight looks too blue in comparison, then add some degree of warming gel to the daylight source to take some of the blue out, again assuming a base color temp on the camera of around 3200K.

 

The blue saturation of the moonlight is also dependent on its exposure, a brighter moonlight will look less saturated than one that is exposed darker.

Thanks David. And what is the common approach.. pass the HMI into a 12x12 frame or bounce it? Bleached muslin ?

[David Mullen ASC]

Whether your moonlight is hard or soft is a creative choice.

[Ruth Vilas]

Thanks! When mixing sources in digital cameras usually I see people using 3800WB instead of 3200 WB, so I calculated the equivalent color temperatures of the moonlight source using mired shift

WB 3200
• Traditional Full Blue moonlight: lights at 5600K (-133 mired)
• Less blue moonlight: lights at 4500K (-90 mired).

 

WB 3800
• Traditional Full Blue moonlight: Lights at ~7700K 
• Less blue moonlight: lights at ~5800K.

 

Does this calculation is correct for achieving the same look? 



 

Edited February 25 by Ruth Vilas

[Nicolas POISSON]

The value of 3800K is probably just for convenience. When you want to keep the look of warm 3200K tungsten and cool 5600K moonlight, you will often end up setting your WB around 4000K. The advantage is that there is no need to gel anything. But maybe you find the moonlight not cool enough, or the tungsten not warm enough.

Say the look of 3200K tungsten is OK with a WB of 3800K (Mired Shift of 49) but moonlight is not cool enough. Then yes, setting your moonlight at 7700K will give you the same blueish light as if you had set WB at 3200K with 5600K moonlight (mired shift of -134 in both cases).

But maybe you cannot change the colour temperature of the moonlight, it is fixed at 5600K. Then you set your WB at 3200K (mired shift of -134), and change the tungsten at 2800K (Mired shift of 49).

Many LEDs can be set in a rather wide range of colour temperature. You have some latitude with the relative settings of moonlight cool white, tungsten warm white, and camera WB. Still, if you set the camera WB too close to one side of the range, you may not have enough latitude. So you will target the intermediate colour temperature. Here are some examples of four LED devices, with their colour temperature range. As you can see, the central colour temperature remains around 4000K:

3200~5600 => 4100K
2500~8000 => 3800K
2500~10000 => 4000K
3000~6500 => 4100K

It is not a rule. If you mix LED devices simulating tungsten and HMI, you might prefer to configure all the set according to the HMIs.

Edited February 26 by Nicolas POISSON