Choice of bulb temperature and white balancing

M

Mike Caffrey

Member
I bought the different temperature bulbs, warm, cool and "bright white" which sems pretty neutral.

Assuming that I'm going for a neutral effect, is there ever a time when I'd need all three temperatures?

Suppose, I just carried neutral bulbs for shootin inside. If there's no natural light, I could use the neutral and white balance for the ambient light which is going ot be warm, and this should be fine.

If I was near a window, I could probably do the same, or use the cool bulbs to match the natural light and then color balance for the outdoor light. The same works for someone sitting near a computer monitor.

I can't come up with a scenario where I woulnd't be able to function wihtout bringing warm bulbs. Is there a situation that I'm overlooking?

If I had a lot of mixed sources, couldn't I just increas the neutral/cool light and use a lower shutter speed to diute the warm?


Do cameras prefer warm, cool or neutral light?
 
There is no neutral light. They all have finite, fixed color temperatures. You may prefer a specific bulb, but it is by no means neutral.

The "best" light is typically daylight (the DVX 5.6k preset), and most CCD's perform best with this light, because it contains a lot of blue light, which is the toughest light to get through the CCD filters. So, set your DVX to the 5.6k preset and look at each of the lights. The one that looks neutral with that preset is the "best" one.

The most important thing is not to mix different color temperatures. You cannot dilute or counteract one with the other. They should not be mixed (unless intentionally). So, there should never be a cricumstance where you need all three bulbs, but it does help to have a variety at your disposal for different situations.

Most likely you will want the warm bulbs for matching practical lights when shooting indoors. If you want to kill the practicals and open a window shade, you can match the cool to the daylight coming in. For outdoors, again, probably the cool bulbs.

The bulbs should have Kelvin temp ratings, and a CRI rating. You want a CRI rating above 90, preferably 95 or higher. You want daylight bulbs as close to 5.6k as possible, and warm or indoor bulbs close to 3.2k.
 
What's the midpoint between 5.6 and 3.2 considered?

As far as diluting/counteracting, my experience has been that you can. Mayb it's simply by using more cool light than warm ligh so that you can't see the warm light, but it's certianly worked.

I've been trying to figureout if I could get away with carrying only 2 temperatures - the cool for matching natural and the inbetween color, whihc ouwld be the main choice. The only time I'd use the cool is when there's so much natural light that I have to match it.

My thought with practicals, is that if I throw more light than they create, you won't see the color they give off - also cutting down on glare. Regardless, if there's not cool light it doesn't matter, becuase I'd white balance for practical temperature anyway becuase this middle temperature seems to blend either way. I don't know what to call it other than neutral.

I did have the sense that using the cool light and white balancing looked better than the warm light and white balancing. But it was so close, I wasn't sure.

I know that blue has the most distortion. Does using a lot of the cool/blue light cut down on that?
 
Mike,

Sorry, light just doesn't work that way. If you have mixed lighting, you will be able to tell. If you did find bulbs at a midpoint (which they don't really make, because they have no practical application), they would look warm compared to daylight and cool compared to tungsten.

There's no magic here, you need to have tungsten-balanced lights for some situations and daylight-balanced lights for other situations. The only real work-around is to use daylight-balanced lights and have CTO gels around to correct those light to tungsten balance as necessary.

Josh
 
which of the two gels loose more light? The ctb or cto?

im thinking the cto... just cause blue is very pale compared ot the dense looking orange.
 
CTB eats a lot more light than CTO. CTB absorbs 2 stops and CTO takes 1/2 stop (if I remember correctly).
 
Is there such thing as a colorless light or a white light?

What I find is that these bulbs don't really have a look. Tungesten looks warm nexto them and daylight looks cool.


And you could uses daylight balanced lights indoors without gels. As longs as there is more of that temperature light than the tungsten you balance for cool.
 
HorseFilms said:
CTB eats a lot more light than CTO. CTB absorbs 2 stops and CTO takes 1/2 stop (if I remember correctly).
Click to expand...

that really surprises me.
 
PaPa said:
that really surprises me.
Click to expand...
should be easy enough to check right? assuming u have both gels available. also, the human eye isnt equally sensitive to all color frequencies so test in-camera
 
depending on your scene .... you'll have to decide if mix lights works ... the world is NOT 5500K or 3200K - it is a mix of different color sources ...
you'll find on commercials/movies different lights on the sets will have different gels on them because they want to mix the temps for effect ... walking into a liv and everying at 3200k might work if you want X effect .. or you could throw in some 2700k household bulbs into practicals for Y effect - when persons walks down hallway you might have a cooler light coming out of bathroom and warmer light out of bedrooms ? all depends ... you are in control !!!
 
Of course you would use both daylight and tungsten in the same shot. You can have one side in warm and one in cool so you have a nice contrast.
 
donatello said:
depending on your scene .... you'll have to decide if mix lights works ... the world is NOT 5500K or 3200K - it is a mix of different color sources ...
you'll find on commercials/movies different lights on the sets will have different gels on them because they want to mix the temps for effect ... walking into a liv and everying at 3200k might work if you want X effect .. or you could throw in some 2700k household bulbs into practicals for Y effect - when persons walks down hallway you might have a cooler light coming out of bathroom and warmer light out of bedrooms ? all depends ... you are in control !!!
Click to expand...
What you mentioned doesn't mean mixing different lights, it's just using them separately.
What was discussed is about using them to light one spot I guess...which its difference in temperature can be recognized by human eye, again I guess!
 
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