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Color Temperature of Different HMI Lights


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Hi,

I need to know, color temperature of HMI is said to be Daylight balanced i.e 5600K, so all HMI's of different power like 4K,5K,6K,12K etc have the same temperature?

Also, what is the box of 6-8 solar tungsten light is called which we usually see in music videos?

 

Regards

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7 hours ago, Fiza Chughtai said:

all HMI's of different power like 4K,5K,6K,12K etc have the same temperature?

HMI lamps for motion picture use are all daylight balanced.

7 hours ago, Fiza Chughtai said:

what is the box of 6-8 solar tungsten light is called which we usually see in music videos?

I don't know exactly what you're referring to, but it sounds like it could be a lamp known as a Mini-Brute. They have 4, 6, 8, or 9 tungsten par globes in them.

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Thank you Stuart for replying.

Yes you are right about the Brute..I was asking something like that but bigger in size.

Regarding color temp of HMI of different powers, are they all 5600??

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19 minutes ago, Fiza Chughtai said:

Regarding color temp of HMI of different powers, are they all 5600??

By design all HMIs are the same colour temperature.

They tend to get a bit cooler and greener as the bulbs age, so if it's critical that you have several that match, some people will spend time testing out the exact ones they're going to be using, replacing bulbs as necessary or establishing per-light filter packs to match them.

P

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1 hour ago, Phil Rhodes said:

By design all HMIs are the same colour temperature.

They tend to get a bit cooler and greener as the bulbs age, so if it's critical that you have several that match, some people will spend time testing out the exact ones they're going to be using, replacing bulbs as necessary or establishing per-light filter packs to match them.

P

Ok thanks Phil, so if all HMIs are nearly 5600K that is white day light, then how does in most of the Hollywood movies in night shots blue light is shown by the use of HMI...is that cz of the use of CTB? is this possible for any HMI to generate blue light without CTB?

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2 hours ago, Fiza Chughtai said:

Yes you are right about the Brute..I was asking something like that but bigger in size.

There are larger versions known as Maxi-Brutes or Dinos, but they have more lamps, usually 12 or 24.

2 hours ago, Fiza Chughtai said:

Regarding color temp of HMI of different powers, are they all 5600??

Yes. They are all daylight balanced, therefore 5600K

6 minutes ago, Fiza Chughtai said:

how does in most of the Hollywood movies in night shots blue light is shown by the use of HMI...is that cz of the use of CTB? is this possible for any HMI to generate blue light without CTB?

If you shoot daylight balanced lamps with a tungsten balanced camera or film stock, they will appear cold and blue. This is basic color temperature theory.

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1 hour ago, Stuart Brereton said:

If you shoot daylight balanced lamps with a tungsten balanced camera or film stock, they will appear cold and blue. This is basic color temperature theory.

So what is the correct way?..use CTB on HMI or white balance your Digital  camera on Tungsten?

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3 hours ago, Fiza Chughtai said:

So what is the correct way?..use CTB on HMI or white balance your Digital  camera on Tungsten?

You can do it either way. If the HMI is your only light source, it might be easier to change your white balance, but if you have other light sources in shot which would also be affected by changing the white balance, you might choose to alter the color with gel instead. There is no "correct" way to do it. It just depends on the needs of the shot.

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4 hours ago, Stuart Brereton said:

You can do it either way. If the HMI is your only light source, it might be easier to change your white balance, but if you have other light sources in shot which would also be affected by changing the white balance, you might choose to alter the color with gel instead. There is no "correct" way to do it. It just depends on the needs of the shot.

Got it!!..so for most of the scenerios and to make it a habit, using Gels seems more appropriate.

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8 hours ago, Fiza Chughtai said:

Got it!!..so for most of the scenerios and to make it a habit, using Gels seems more appropriate.

No. Usually when creating moonlight with an HMI you would use a tungsten white balance, as often your other, practical sources are tungsten balanced. CTB gels absorb a lot of light, so are generally not used unless necessary.

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1 hour ago, Stuart Brereton said:

No. Usually when creating moonlight with an HMI you would use a tungsten white balance, as often your other, practical sources are tungsten balanced. CTB gels absorb a lot of light, so are generally not used unless necessary.

Thank you, your DP pic is Florescent light on the background wall and LED or HMI at 5600 white balance camera? or is it tungsten white balanced camera with HMI in BG and tungsten on your face?

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2 hours ago, Fiza Chughtai said:

Thank you, your DP pic is Florescent light on the background wall and LED or HMI at 5600 white balance camera? or is it tungsten white balanced camera with HMI in BG and tungsten on your face?

My profile pic was taken on a set which was lit with a daylight balanced kinoflo as a toplight. The camera was white balanced to 4300K so that the kino tube would appear slightly cold and blue. It's the same light on the wall as on my face.

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  • 2 weeks later...
On 2/10/2021 at 10:47 PM, Fiza Chughtai said:

Hi,

I need to know, color temperature of HMI is said to be Daylight balanced i.e 5600K, so all HMI's of different power like 4K,5K,6K,12K etc have the same temperature?

Also, what is the box of 6-8 solar tungsten light is called which we usually see in music videos?

 

Regards

Theoretically I would guess all brand new, different wattage of HMI products from the same manufacturer, lamped with globes from the same manufacturer, fed the same voltage and amperage at the same stable frequency would be very close to the same color temp ~5600K.

However we don't live in the world of theory, but the world of reality. On the set you'd possibly have HMI's from several manufacturers, lamped with globes of varying ages so there is a varying disparity in color temps among them. My gaffer used to baseline our lighting package as we started a show. He'd take his 3 color meter and  notate the base color temp of each unit on a piece of camera tape affixed to each head. If needed the units could me nominally balanced by adding 1/8 - 1/4 CTB. Remember too, on Daylite shoots you're using the HMI's so supplement abundant natural daylight so a small variation in color temp tends to get lost. For night shoots, we'd usually go 1/2 CTO's so the "moonlight" ambiance would be half blue compared to our 3200 film balance. Full blue was kind of distracting to me personally. Practicals would read as nominally "white" or slightly warmer if desired.

The multiple fixture light that Mole calls Molefays we used to call them by the number of globes in the fixture such as "9 lites" These took PAR36 globes that were once available with a dichroic (sp?) coating that was (very nominally) daylight temp (they faded fast due to the heat) and a 3200K tungsten globe. I believe the Colortran version was called a Minibrute. The Mole Maxibrute is the one I usually see on music videos and tv productions used as an effect usually drastically dimmed.

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25 minutes ago, Doyle Smith said:

For night shoots, we'd usually go 1/2 CTO's so the "moonlight" ambiance would be half blue compared to our 3200 film balance. Full blue was kind of distracting to me personally. Practicals would read as nominally "white" or slightly warmer if desired.

May you please explain it more. CTO is the orange gel, so it will throw orange tiint..isnt it? so how will it show blue moonlight?

Do you white balance your camera for night shots at 3200? and 5600 only for day shots?

Also, if camera is white balanced at 3200,  wouldnt HMIs will show blue light without help of any gel?

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6 hours ago, Fiza Chughtai said:

May you please explain it more. CTO is the orange gel, so it will throw orange tiint..isnt it? so how will it show blue moonlight?

Half CTO is less orange, so the light is still blue compared to a 3200K-balanced camera.

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2 hours ago, Phil Rhodes said:

Half CTO is less orange, so the light is still blue compared to a 3200K-balanced camera.

Why not white balance 1 or 2 stop over to save the extra step of adding half CTO?

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28 minutes ago, Fiza Chughtai said:

Why not white balance 1 or 2 stop over to save the extra step of adding half CTO?

Stops refer to exposure, usually.

What you seem to be talking about here is balancing at (say) 4200K so that 5600K lighting looks bluish, but not as blue as it would look with the camera balanced to 3200K. That's true and a completely reasonable way to go. In the end it depends what other light is in use and other practical considerations.

P

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28 minutes ago, Fiza Chughtai said:

Why not white balance 1 or 2 stop over to save the extra step of adding half CTO?

If you're correcting multiple fixtures with multiple bulbs differing in age they all would be marginally different. Also if your supplementing daylight and so on.

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6 minutes ago, Phil Rhodes said:

Pretty much that.

Colour balancing to a certain CT.

Aperture balancing to certain value is called changing stops, but changing certain color temperature from one value to other value cant be called changing color stops?

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Just stopping in to say a majority of HMI bulbs come in closer to 6000k in my experience.

Recently used a Joker 1600, Arri D12 Fresnel and a Arri 1.2k Par and all were slightly different. All had new bulbs. If I remember correctly I had to add 1/8 - Green to the 1.2k Par and looking back should have added a 1/8th CTO to the Joker to make them closer. I used a color meter on set, which I rarely use so luckily I tossed it in the bag!

 

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